Go Tony - go! And don't let the small children hold you back - nobody else on the flight I was on last spring did - they pretty much yodel in concert with each other
I am pretty sure that my flight from Vancouver to Hong Kong was about 13 hours (Cathay Pacific) and the return flight was about 11 hours. The flight from Hong Kong to Bangkok was another 5 hours and then on to Koh Samui for 4 days and then Koh Tao for 6 days then return to Hong Kong for 4 days. The most wonderful vacation I have ever been on and if you are looking at going to Thailand consider those 2 islands. Beautiful places - some of the (apparently) best diving in SE Asia. Transportation is no problem at all once you are there and neither is the language. Diving (including instruction and certification) is cheap and so is everything else. The Thai people are amazing. I went by myself and at no time did I feel uncomfortable or unsafe. And the thing about going by yourself is you really spend a lot of time just "people watching". In the just about 2 weeks that I was there I did not hear raised voices by any Thai people at all (the tourists were another matter - particularly those from Northern Europe).