An alternative to a hotel room in BKK would be to rent a condo :-
This one's near Asoke station
http://bangkok.craigslist.co.th/vac/3169130829.html
or this one on Suk. soi 13
http://bangkok.craigslist.co.th/vac/3168179097.html
For other locations in Thailand,click on the "vacation rentals",there are many for BKK,Pattaya,Phuket,Chaing Mai,Samui,etc.
Worth a look.