Thank you for your offer, but we’re leaving for the US in a couple of days and won’t be back until the end of the month. The main reason we’re leaving in April is because of the dreaded Songkran holiday from April 13-15, or until April 17 this year to compensate for part of it being on the weekend.
Yes, a taxi into Bangkok from Suvarnabhumi Airport should run about 300 baht including Expressway tolls and the 50-baht surcharge for the airport taxi. There have been problems of late with horrendous queues at Immigration – 2-3 hours the norm – but supposedly these are getting better. I’m sure I don’t have to tell you to ignore the unofficial taxi touts.
As for travel to neighboring countries, I can tell you that among those you’ve listed, Hong Kong – not a country, but let’s not quibble – is the farthest. Takes a few hours to fly there. But Americans get visa on arrival, unless that’s changed drastically. Vietnam is very nice, and if it’s just a quick trip, then I recommend Hanoi/Halong Bay or even central Vietnam – Hue, Hoi An – over Ho Chi Minh City, which, although worth a look too, the wife and I both have found to be less interesting than the other places and more of your generic Asian metropolis. For Americans, however, Vietnam has the highest visa fee of all the Asean – the 10-member Association of Southeast Asian Nations. I’m thinking it was US$30 when I got mine two years ago. There is no visa-on-arrival for US citizens, so you must arrange it ahead of time at the Vietnamese Embassy in Bangkok (or where you are now if there’s one closer). This can take up to three days but can be expedited with payment of a rush fee (legitimate, not a bribe).
If you’re going to be in Surat Thani, then Malaysia is closest, of course. (There are no land crossings into Burma, except for day trip to Victoria’s Point.) It’s still at least a day’s journey to the border by bus or train, and I’d be wary of entering the Deep South of Thailand right now. There were some ferocious bombings down there over the weekend, and the authorities are braced for more. Part of the almost decade-old insurgency in that part. But I like Malaysia, and a flight to Kuala Lumpur from Bangkok is pretty quick. If you do cross the land border, Peneng – which has an airport too – resembles what Hong Kong and Singapore must have looked like before modernization. No visa required for trips to Malaysia.
For Indonesia, Bali is nice, and you can fly there nonstop from Bangkok. About 3-1/2 hours if I remember correctly. (2-1/2? Something like that.) I highly recommend the Ubud inland toward the center, and dolphin-watching on the north shore at Lovina Beach. From there it’s an hour’s flight to Yogyakarta in southern Java, site of the ancient Borobudur (Buddhist) and Prambanan (Hindu) temples. You may have to arrange a visa beforehand; check with the embassy.
Besides Malaysia, Singapore also does not require a visa. Laos and Cambodia do require visas, but you can pay for them on arrival. (You could arrange for them beforehand too, but both the Cambodian and the Lao embassies are now over in the Ramkhamhaeng area, very far and inconvenient to get to.) You can fly directly to Siem Reap, where Angkor Wat is, but it’s an expensive flight – Bangkok Airways has a monopolyon the route. It’s possible to go overland from the Thai border, which takes just a couple of hours, and the road is paved all the way now, I hear.
Traveling solo is pretty much no problem in any of these places. Costs will be equal to or (mostly) less than in Thailand, except for Singapore and Hong Kong of course.