Answer
Doi Suthep: Stunning views of the city at dawn. Mon Cham: A beautiful spot with rolling hills and mist. Doi Inthanon: Thailand's highest peak, perfect for early risers. Mountain Viewpoints, Sunrise and Mist can be approached by first deciding the location, time available, transport and level of activity that suits the trip. Use the options in the question as a starting point, then compare current provider information and recent local conditions before making a booking.
Practical Chiang Mai planning note: Check weather, road conditions, fitness requirements, footwear, insurance and the provider's safety practices before setting out. Mountain conditions can change faster than conditions in the city, and mobile coverage may be limited in some areas.