My wife and I are headed to Chiang Rai for a few days in December. We've been to Chiang Mai and loved wandering the city for a couple of days. (We found that 2 and a half days of wandering CM was perfect.) Given that Chiang Rai itself appears to be significantly smaller than CM, if you were to simply wander about the city, how long would you allocate?
Also we were thinking of renting a car after spending a couple days in CR and heading up to Chiang Saen for the morning, then overnight in Chiang Khong. Then spend the next day driving to Phayao with an overnight in Phayao, spend the day wandering around Phayao and then back to the CR airport for our flight south. Does that sound like a feasible itinerary...or too jam-packed?