that's interesting. I'm Australian and while most other factors were priorities to moving to Thailand, getting away from Australians was one of the reasons why I moved
you won't have an issue. I just flew in from KL Malaysia on my 3rd 30 day stamp. Since late November last year this is my 9th month in the country. 2 60 day visas, 2 extensions, 2 land border runs and now re entry at don muang this last time. I was sure to be interrogated but the officer didn't even ask to see my exit flight. So you'll be more extremely unlucky to be denied than lucky to be let in. Enjoy your stay
Impossible too calculate so I can only give you my budget living in bang saray which is between 40-45k baht a month. But that's just living expenses such as rent, utilities, food, sundries, internet, bike fuel (own my own bike).