One of the disadvantages to early May is that many of the tourist attractions have not yet opened for the season. Gillette Castle is one of those attractions. It is located in a state park, a great place for walking and picnicking. The "castle" itself is located at the highest point on the grounds, with a wonderful view of the Connecticut River (to me, the castle looks like something that was built by the Flintstones!), which makes a tour of the inside even more intriguing! But the tours don't begin until Memorial Day. You can walk freely around the outside of the building and look into the windows, but it's not quite the same. I think I may go back in the early fall just to have a picnic and do the tour. I've been told that the area is very crowded during the summer months.
The castle was actually the home of William Gillette, who played Sherlock Holmes on the Broadway stage.