Wanting that experience is a matter of spending enough money, while you quote your only reason to be here is financial reasons, then you can not really expect to find that. But yes it comes down to the more populair and expensive farang places in Phuket and Bangkok most likely. Pattaya is also as english as it can get, for a budget still possible, but I assume you look for that other end, which is expensive too.
Also the Thais are different in the higher-end level, they usually are as much foreigner as any other foreigner, well travelled, speaking good english etc. I always call this country the country of countries. There are many different worlds to live in here.