Thanks, everyone. I can see that my question may not have an obvious answer.

I think we may only spend 2 nights, and then will probably want to get to the train station over an overnight train to Chiang Mai. We'll mostly be doing the temples and possibly some shopping (I haven't researched the BKK shopping scene: is it handicrafts or knock-off clothing like Beijing/Shanghai)?

From my experiences elsewhere in Asia, I know that traffic can be a huge consideration in deciding where to stay. So, yes, I would greatly appreciate a recommendation on where to stay based on ease of getting around to the tourist haunts.