a taxi into town is about $12 , so that the easy way , 30-40 minutes to get into town
normally I would say get a hotel less than 5 minute walk from BTS or MRT Subway , , BUT the BTS does not run all night , and the morning airport BTS - Train does not start early enough for you to get to the airport in time
I am not sure what you plan on doing but Chinatown is interesting