Solo trip to Boston? Best advice and tips

Hey guys, so I don't travel much but I've been meaning to. I've been pushing it off year after year. So I decided to do a solo trip to downtown Boston in December (not sure if that's a good idea due to the cold). But I've heard it's beautiful and wanted to try it out and its the only time I have off. I'm on a budget and didn't want to factor in a retal car, I don't mind walking. Ive been doing some research and wanted to know if there was a sweet spot to stay in downtown. I'm interested in museums​, aquarium, cafe shops, Trails (bc i love running ), and I'm a foodie. So far I saw the Hyatt Regency Boston, Sheraton Marriott, and Harborside Inn hotels. Some place safe for a female in her 20s, nothing crazy or fancy . Any suggestions on the best hotel wound be helpful. Even another state I'm open to.