Doing a google maps search of “Philadelphia to San Francisco”, I think the Utah suggestions are wonderful.
But the first several hundred miles are going to be pretty boring. I’m going to suggest altering the route a bit to head through:
- Washington DC - Okay, you may be from Philly, but it’s a wonderful must-see for any American trip, and there’s a bazillion things to see and do.
- St. Louis Arch - Not much of an original suggestion, but the map is still pushing me north and through St. Louis - It’s a cliched tourist site, but it’s an easy hour long tour, and interesting, considering the trip ahead of you.
- Kansas City BBQ - I’m not going to get into a BBQ debate, but KC BBQ is excellent, regardless of your preference. And as a bonus, it’s actually on the route. Stop by Arthur Bryants or Gates BBQ, both have easy exits from the highway. (Get ribs at Gates, and a sandwich at Bryant’s - I prefer the beef and pork combo.)
- Denver - There has to be something to see here, right? Locals want to chime in?
- All the Utah stuff and beyond.

If you’re down around Vegas, of course there’s the Hoover Dam close by, and, just north of that, the Valley of Fire State Park, also very cool. In Salt Lake City, the Mormon Convention Center, across the street from the Tabernacle, offers free tours and is a huge, magnificent building.