Just back from a quick weekend getaway to Kingston and thought I'd post my review.
We stayed at the Holiday Inn Express just off the 401. Fabulous. The hotel is clean and well maintained. Every single staff member we encountered was exceptionally friendly and helpful. Great room, great pool, great breakfast. We will definitely be staying here again.
As for what to do while in town... nothing. Every museum/attraction that we were interested in was closed- either for the season or on the weekend. They did have a great skating rink set up downtown, but we're not skaters.
I would not recommend Kingston as a destination in the winter, however we're looking forward to checking it out this summer.