I would go to Loei. There is a bar scene including some shockingly "hip" nightclubs and otherwise, its absolutely lovely there a great little town, good food, and the countryside is just gorgeous.
I would float the Huai Krathing Reservoir every day of my life if I could. Nothing like being paddled out beer in the middle of a giant body of water by some poor sap clearing ten baht a go. Its just too fucking Thailand man.
https://www.tripadvisor.com/Attracti..._Province.html
There is also a wine vineyard or two within striking distance.
If you want to relax in a nice small town with plenty of scenary a motorbike ride away, its tough to top Loei.