Filled with excitement, we flew to the island of Phu Quoc for my birthday weekend, intent on sun, sea and relaxation after the hustle and bustle of Saigon. The flight there was simply stunning, as we soared over shimmering clear blue ocean and the verdant green north of the island's forests. It really felt like we were off on an adventure.

Apparently the government has big plans for turning Phu Quoc into a major tourist destination. Fortunately plans to execute this are clearly still in their very early stages, as we discovered pretty soon after arrival. The island remains an unspoilt paradise, with deserted beaches and an endless row of palm trees all the way down the west coast, pepper farms dotted through the middle.

For the most part, there is no road to speak of – small 500m patches of tarmac, seemingly randomly placed, break the monotony of bumpy rust-coloured dirt tracks. The signs of proper road construction are everywhere; but again, progress seems to be slow. Learning that the drive to our resort was the best part of an hour's journey from the airport, we rejected our motorbike pick up and opted for a taxi – thank God! I am astounded the car suspension survived the trip, so I think our experience on the back of a motorbike, laden down with 15kg rucksacks, would have been pretty hellish. Clearly someone has briefed the taxi drivers here on the sort of music that westerners like, and we spent the next hour or so enjoying instrumental versions of holiday classics including 'Guantanamera' and 'Careless Whisper,' as well as 'My Heart Will Go On,' just for James.

We were looking for deserted island paradise, and it's fair to say we found it. We were staying in an isolated resort to the north-west of Phu Quoc, which lay directly on the beach, complete with shaded hammocks that we spent many hours dozing in and cute little beach huts. It was a proper island getaway. However, with hindsight Phu Quoc seems to be the kind of place where money talks, and so our backpacker budget meant the accommodation was pretty 'rustic' – no air conditioning (which came at a $20 a night premium), no hot water and no electricity during daylight hours. Despite this, we actually really enjoyed the experience – even though James nearly expired part-way through the middle of the first night as a result of the heat!

We arrived at lunchtime and by 2.30pm we were settled on our own private beach, enjoying the sea breeze after the stifling heat of Saigon. Later we watched the sunset with only a couple of local fishermen and some cows for company. It was bliss.

My birthday itself was more adventurous than previous years: in the absence of public transport, we opted to hire a motorbike for the day (again, sorry mums, we promise we're not about to make a habit of it) and explore our surroundings. More by luck than judgement we made it all the way down the west coast to the port of An Thoi in the very southern tip, passing beautiful beaches and yet also some of the poorest Vietnamese homes we've encountered on the whole trip – huts literally fashioned from wood, palm leaves and, in a few cases, odd pieces of tarpaulin and corrugated metal. Despite this, most homes still (of course) have TV aerials. We had a slap-up lunch at one of the many resorts along Long Beach, along with a celebratory birthday beer.

Unfortunately, on the way home, disaster struck, and we managed to get a puncture, resulting in a massively flat tyre (even I noticed it was flat, which shows how bad it was). Through the wonders of sign language we tried to get a local mechanic to pump up the air, but to no avail – the tyre was well and truly dead. After a phone call to the resort owner, Mr Phuong, he agreed, somewhat bemusedly, to come and rescue us. There was nothing for it but to head back to our lunchtime restaurant and have another beer. Some 45 minutes later, we realised why he'd sounded bemused: he thought we were lost and couldn't find our way home again! We quickly put him right and so I found myself, on my birthday, watching the same mechanic from earlier performing a tyre change. Fortunately it was a quick job and we were soon chasing the sunset back to the resort. And I've learnt a lot about tyres as a result!

To get from Hoi An to Nha Trang we took an overnight sleeper bus, leaving at 1830 to arrive by the beach in Nha Trang 12 hours later. We subsequently learned that this particular sleeper bus route is known amongst travellers as 'The Hell Bus'.

The layout of a sleeper bus is similar to how I imagine a submarine sleeping quarters would be, if that submarine was designed and manned by dwarf contortionists. Each person is allocated a reclining chair/bed, with a leg compartment neatly tucked under the chair of the person in front. There are around 7 chair/beds in each row, three rows to a level, and two levels on the bus – about 40 people per bus in total. Unfortunately, the leg compartments are designed to be a snug fit for the average Vietnamese person - for anyone taller than about 5'5'' they're pretty much useless. I spent most of the night exploring a series of equally uncomfortable configurations of feet, knees and legs before landing on a complicated half-foetal position that enabled me to wedge my body into the seat and prevent my falling out whenever the bus went round a corner.

The tight fit would have been fine for an hour or two, had we been on a straight-run down a motorway. But motorways don't really exist in Vietnam. And our route took us down the coast on a two-lane road that wound around an endless series of hairpin bends. The driver was either super-confident or suicidal, as his preferred strategy for taking these blind corners was a) top speed, and b) simaltaneously overtaking the more sensible slow moving traffic on the wrong side of the road. This led to a couple of near-misses, where all passengers were suddenly woken by the flashing headlights and horns of oncoming traffic bearing down on us at full speed, with us on the wrong side of the road, hemmed-in by a cliff on one side and the 'slow moving' traffic we were in the process of overtaking on the other. Miraculously we survived every time, although I have a feeling that without the cover of darkness we would have seen the roadside littered with the rusting husks of less fortunate buses.

Even the tight fit AND manic driving would have been just about manageable, had the bus been clean. However whilst first appearances were good, when the lights went at our first rest stop I observed a not-insignificant number of cockroaches scrabbling for cover, disappearing back under seats and floorboards. I jerked awake from my foetal position a couple of times in the night due to a skin-crawling, clicking sound near my ears.

Leaving Nha Trang, we took the train. The day train.

I've heard the song 'My Heart Will Go On' by Celine Dion four times in the last three days. Once is more than enough.

The first time, they turned it on full blast in a cafe in Hoi An where we were quietly having an aperitif - immediately forfeiting their tip, and forcing us to leave.

We then headed to a French-Vietnamese restaurant for dinner. It seemed like a really nice place, until I realised they were playing an instrumental version of the exact same song in the background.

The next day in Nha Trang we ate at a traditional seafood diner and yet again the playlist included The Song (followed, strangely, by a Timbaland track).

At this point a couple of hypotheses were developing in my head. Did Vietnamese people think that Westerners have some kind of deep affinity for Celine Dion? Or maybe it was the reverse - maybe they were fully aware of just how repulsive the song is, and play it to hurry people along and increase turnover, like dance music in Macdonalds but more effective.

Arriving in Saigon last night, just as the safety locks clicked on in the taxi from the station, 'My Heart...' burst forth from the car speakers once more. This time however it was definitely a local radio station. So scenario three seems likely: The Vietnamese just love Celine. God help them.

On the train to Hue, I suddenly realised just how green Vietnam is. It seems a stupid thing to say having already been travelling around the country for two weeks, but after two months in the dust and concrete of Japan and China, I think I simply didn't recognise the colour. Waking up on the overnight train south, you find yourself surrounded by the rich emerald green of rice fields and the deep jungle shades of the mountains. Here and there, gleaming white family shrines poke their heads above the top of the rice stalks – covertly watching their descendents work the fields.