The accommodation offer in North Vietnam is limited. There are many hotels, but most of them belong to a similar category. I could only find one good hotel in Cao Bang. If you come on an organized tour, you do not have to worry. The guide will look for a hotel. If you do not have a guide, you will easily find a place to sleep. Prices are low. You should bargain a little before accepting the room. Air conditioned may not be necessary, but a mosquito nets are.