Originally Posted by
FlyTheFriendlyMonkey
I'll second this. If you really enjoy the outdoors, Chaing Rai is a good option. If not, it's hands down Chiang Mai. I would strongly suggest picking only one of the two.
To piggyback onto everyone's comment about picking one or the other, while I've never been to Chiang Rai, I was in Chiang Mai for 5 days a year ago and found it to be a good amount of time. Being there for 2-3 days would be extremely rushed, plus you would need to account for the loss in time due to traveling between the two.