travel from Pontresina Swizerland to Lake Como

Our family will be spending 3 days in Pontresina in early June. Thought we would visit Lake Como for 2 or 3 nights. We are traveling by train with a Swiss pass so would probably arrive by way of the Bernina Express bus. What town would you suggest we stay in and can you recommend any 3 star hotels. We will then train
to Zurich to fly home.