Certainly July is not among the good time to visit but now many tourist visit during monsoon also.You can get good deals at hotels.You can plan Gangtok, Ravangla, Pelling and Darjeeling.If going in July then my suggestion would be to have your itinerary flexible and avoid booking cab/hotel in advance.
Book them on the spot as per requirement.I had once visitedSikkim/Darjeeling during 1st week of July.My trip was memorable.
