Luang Prabang or Khao Lak
 

Looking to spend 7 or 8 nights in either area. Wanting to relax, swim in waterfalls or hotsprings. Good food, massages. Nice atmosphere.

Beach or river not a big deal. Not looking to do too much or move around to other towns. Only want some day trips.

Which would you recommend?

It sounds like a beach area like Khao Las would better suit your agenda.

While I loved LP when I was there years ago, it was then a sleepy little town. It is now overrun with tourists. I'm sure you can still find quiet wats and less crowded places, but it is no longer a sleepy small town. No hot springs that I know of near LP. a couple of rivers (really more like streams) where people go to take a dip - not large enough for swimming.

Khao Lak is now overrun with Chinese tourists but at least it is spread out so only hotels packed. Not many trips to go on there except waterfall which should be good as we have had loads of rain. Good for relaxing on the beach.

LP seemed an haven of peace and quiet compared to Phuket, the centre was busy at night but not enough to be a problem, during the day the streets were empty. Nice waterfall with Bear Sanctuary where people were swimming in all the pools, that was fairly busy.