Vacation spots in Maine, New Hampshire?

I am looking for a place to go for a one week vacation with my husband and 2 and a half year old girl this summer. We really like the idea of a cottage on a lake but we would also like to have somewhere to go indoors with a toddler if the weather is no good. Last year, it rained almost all week and we were in the middle of nowhere! Any links to a website would be great too. Thanks!