re: Is Philadelphia a decent long weekend trip?

Didn't see it mentioned, but the US Mint is pretty good museum. It's free and you can get through it in 30 minutes if you don't want to spend a lot of time there. It's right down the street from Independence Hall and the Liberty Bell. Ben Franklin's grave is across the street.

You should be able to walk wherever you want if you're staying close to city center, but ubers are very easy. The subway is efficient, but it's pretty disgusting and I'm not one to really get grossed out by things like that. I've been on it plenty of times as my sister in law and her husband live about a half mile south of Rittenhouse Square. Philly is gritty to say the least, but if you're only going for a weekend, you should be able to stay busy and see enough.