One of my favorite historic trips of all time, was to Gettysburg, PA. It was actually probably one of the least expensive trips that I have been, in which I had to travel such a distance.
I enjoyed the fact that most everything we wanted to visit was within a pretty small radius. The most driving we did on our trip was along the self-guided auto tour. And even then, we were stopping so often, that it did not seem like we had traveled much of a distance at all.
When you are on the auto tour, be sure and stop and see all of the sites. There are few that have a very, very small hike. The view and sites are well worth the trek.
Dinner at Mamma Ventura was simply delicious. It is a casual Italian restaurant and very well priced. The atmosphere is extremely down to earth, and did I say the food was delicious! I consider myself an Italian restaurant connoisseur, and this one tops the charts!
Here's my article on Thrifter, http://trifter.com/usa-canada/pennsylvania/budget-travel-to-gettysburg-pennsylvania/, which gives quite a bit more detail about the free things to see and do while you are visiting Gettysburg.
If you only travel to one historical town in your lifetime, Gettysburg is the place to go.