If you haven't ridden for a while then be prepared to face some changes. The pace of motorcycle development has never been as high. And though there's no doubt motorcycles are safer and more capable than ever, the overall performance of them is in a different league to how it was as little as ten years ago, even a small engine motorcycle can surprise you if not careful. And the amount of traffic using the roads has increased dramatically.
To stand a chance of getting through the earliest days of your 'comeback' it's a good idea to take things easy. It doesn't matter how good and experienced you thought you were back in 'your day', the combination of being rusty and jumping on a much different sort of motorcycle to what you once were used to can be fraught with risk.
Adjusting to your new world takes time and getting some help can be a good idea. Be realistic and don't for god's sake think that being up to the job in your younger days is enough to cope with riding after a break from it all. Most important thing you need to remember is that motorcycling in Thailand is different.
Training will help you to familiarize yourself with the new challenge. Don't be too proud to take some.
If I don't ride for a week or change the motorcycle I ride daily, I need a little time to get back into things fully.
If you've had a break from biking, be patient to avoid having another very different break!