The Flight 93 National Memorial commemorates those who died attempting to take back their flight from terrorists on 9/11, and in doing so likely prevented an attack on the Capitol.
Parking is available for large trucks and buses, but I’m glad there weren’t a lot of other visitors when I visited this week. The lot might have been difficult to maneuver in if it had been full. Truckers have a couple of different possible safe routes in, but I prefer taking the Pennsylvania Turnpike exit 110 in Somerset to PA-281 north, to US-30 east, to the park entrance. The drive in from the turnpike is about 20 miles and 30 minutes. There is one tricky hairpin turn on the way back as you go from US-30 back to PA-281, otherwise the trip is a snap.
After visiting the memorial, consider stopping in Somerset. Before hopping back onto the turnpike, consider parking at the truck plaza and walk to any number of decent restaurants. I recommend the Summit Diner, a short walk from the truck stop.