We were there last year and found Chiang Mai to be overrun with tourists (of course, we contributed to the collection). So you will find people everywhere trying to sell you trek opportunities. We were just passing through on our way to Laos, so didn't need (or want treks). I second the choice of eating in markets. We found the food there to be about the worst of our entire trip (about 24 days total). My reviews were:

Then the train to CHIANG MAI (and snacks). The top recommendation there was Aroon Rai almost opposite the East Gate (45 Kotchasam Road). Pork Curry with Ginger (Chiang Mai Style), Pork Pad Thai and Sticky Rice for B800 ($20). Very disappointing. Greasy, overcooked and showing no trace of fresh spices. Also ate at The Gallery (25-29 Charoenrat Rd), on the opposite side of the River right on the water reputedly the finest dining in Chiang Mai. Gorgeous location and reasonably romantic, but also notable for being filled with Austrian tourists. Had Ta Bing (deep fried pumpkin with sweet and sour dip) soggy and greasy and left most of this; Nam Chub Kai Tod (Chiang Mai sausage with lemon, ginger, chilli and peanuts) this was advertised as coming with egg, but we asked them to hold the egg (which they did) a better choice would have been to hold everything else just inedible!; Tum Ba Nun (jackfruit paste with herbs and spices) served with sticky rice. This was excellent very tasty; Curried crab (the daily special) a lot of work to get the meat from the shell but not bad and quite tasty; and Panaeng Curry Pork fabulous and perfectly spiced. We also ordered a bottle of a 2000 Bordeaux Château Saint-Bo (St Emilion) but they brought the 1999 (far inferior year). After a slapstick exchange, we finally communicated the issue and the 2000 was triumphantly brought to the table with great smiles all round. Success! Or not! The wine was corked! Oh well (we drank it anyway as it was still drinkable, although flawed). A so-so meal with some good dishes. Cost B1600 (just under $40).

Since then I've heard much better things about Aroon Rai, but that's second hand info.

Alan & Catherine