TC

I agree with those who suggest doing only BKK. There is a lot to see and do there. With a group it always takes longer to "get going". You will lose a day each direction moving to Chiang Mai. Better to stay put (the Royal Orchid is a wonderful hotel and location), work with Tong or Tan as your guides (they are quite inexpensive) and make one or two side trips outside the city as well as doing the sights in Bangkok. The shopping alone will take days of your time -- and the spas! I always feel its best to do a few things well than to do many things in a scramble.