Interesting idea but certainly would take some time to plan. I would think October( mid to late) is a likely time. Coming out of rainy season and not so hot. Easier to book rooms at better rates. Boys are same price all year.
Important considerations would be . Bangkok for culture and Fuck Shows and Massages but more expensive.
Pattaya for a never ending supply of boys at lower rates but certainly the tendency is more to Twink then Beef.
Only 90 minutes between the 2 cities so easy to do both.
There are better places for beaches such as Phuket and Hua Hin but the supply of Bars and Boys is much more limited..
In Pattaya you can get fairly nice rooms for under $50 and in Bangkok under $75 but $100 gets you what you would $300 or more for in Brazil, anywhere in Europe and NYC etc.
In Pattaya boys for short time are in the $30 range and all night for $50. If you get the boy from the Bar add a bar fine of $10-$13.
So many boys on Gayromeo, Jack'd , Grinder you can have a boy in your room 24 hours a day.
Bangkok boys start at $50 short time up to $70. Overnights are harder to get in BKK .. Boys are a little more professional. but figure on $100 for any good looking ones.
Bangkok has a much better selection of massage parlors then Pattaya and some really wonderful Tourist things if you can fit it in between SEX.
Happy to help with planning. I will be there Oct 1-26.
You can read my extensive posts in December with photos on: http://www.gaythailand.com/forums/topic/9365-xmas-in-thailand/