Matsumoto is a great little town and Mel and I had a great time there at Xmas. The first place we visited was Matsumoto Jo (castle) one of the 4 castles in Japan that are considered national treasures.
One of the interesting things from my point of view was that firearms are a big part of the display and firing slits for both firearms and archery are built into the castle. I always enjoy making my way through the castles but there is nearly always some places that being 6 foot and having big feet makes getting around a little interesting (^_^)
Unfortunately because of a public holiday we missed out on visiting some of the museums but we did go to the Japan Ukiyo-e Museum which makes a great visit if you are interested in ukiyo-e (Japnaese woodblock prints.)
We were also happily surprised by the variety of foreign food in Matsumoto and our eating adventures included Indonesian, Spanish and English pub food.
If you have a chance, Matsumoto is a great place to visit.