The Lancaster Historical Society runs the Holton House Museum in the Summer at the intersection of routes 2 and 3 at the north end of Main Street. 603-788-3004 (Frugal Ed, FREE)
The Fairbanks Museum in Saint Johnsbury Vermont is well worth visiting. It's a natural history museum with an unusually large and diverse collection. I highly recommend it, and proof of the pudding is that everyone I have sent there has raved about it when we conversed later. To find it, get to St. Johnsbury, then go to the upper plateau in the center of town, It's the large red stone building with the lions in front. It's in an area of huge, beautiful victorian homes, separating them from the business area. (Frugal Ed)
Diagonally across the street and one block down is the St. Johnsbury Athaneum. Both of these marvelous buildings were left by the Fairbanks family of Faibanks Scales. The athaneum houses the oldest unaltered art gallery un the United States. Be sure to go in, and go to the far back of the building. You'll be amazed at what you see! (Frugal Ed) 30 minutes west of Lancaster.
If you want to visit a real hidden treasure, go North from St. Johnsbury about a half an hour on Interstate 93 to the Orleans exit. Go left at the stop sign, and go straight through town. Less than a mile from the exit, is a road to the left, with a sign pointing to the Brownington Old Stone House Museum. It is in a massive granite block building built by the first black college graduate in America to house one of the boarding schools he founded. This is one you don't want to miss. I could write of all the unusual and interesting artifacts on display, but it would take up too much room in your hard drive! Just go there, and tell me what you think! Ask them where the tower is nearby, and you'll see some excellent views too! 802-754-2022
You can e-mail them at: firstname.lastname@example.org
Brownington Old Stone House Museum Web Site 1 hour northwest of Lancaster.
Gorham Historical Society, at the Grand Trunk Railroad Station, Railroad St., Gorham NH. Routes 2 & 16, 1/2 hour east of Lancaster. Has a steam engine, snowplow, caboose, much more. Beautifully restored. Right next to a well equipped playground to let the kids work off some steam! Look for the big wooden moose. 30 minutes east of Lancaster.
Six Gun City. Route 2, about 10 miles east of Lancaster. This is primarily a theme park for kids, but also has a carriage museum with over 100 antique carriages. Adding more every year. 20 minutes east of Lancaster.
Crossroads of America, Route 302 and Trudeau Road, Bethlehem, NH. 25 minutes South of Lancaster. Look in the Bethlehem Antiques section for directions. The only difference is you turn left at the stop sign at the top of Maplewood Hill. This is a large model railroad display with a small museum. 20 Minutes south of Lancaster.
If you're into railroading, you'll want to see the ball signals in Whitefield, NH. It's the last ball signal in the country. About 10 minutes south of Lancaster on route 3 south. Watch for it on the left right after you cross the railroad tracks going south. 10 minutes south of Lancaster.
Hood Museum, Dartmouth College, NH, 1 1/2 hours south of Lancaster.
You'll find these museums very inexpensive, the parking plentiful, and the collections amazing!