If you’re at SPX but want to do some low-impact sight-seeing, F. Scott Fitzgerald’s gravesite might be exactly what you’re looking for. As the name on the headstone implies, Fitzgerald was related to the author of The Star Spangled Banner.
St Mary’s Church is only a few miles up Rockville Pike from SPX, at the the intersection with Viers Mill Road. You’ll know when you get there because the Pike makes a massive curve to the left - almost as if it was trying to avoid the cemetery containing such a historic writer.
To get to St. Mary’s church, you have to go past it and make a right turn at Church Street, then loop back to the church. It’s not a very big graveyard, but finding the grave itself can take a little bit of searching. If I recall correctly, it’s towards the Northeast corner.