Are you sure you don’t have CLT and IAD reversed?
Charlotte is an easy walking airport, Dulles not so much.
Although BA’s new lounge at Dulles is quite nice.
If you land at the end of Charlotte, and need to make your way to the Int’l area....it’s a hefty walk. I’d say Philly has the same problem.
I had some travel agent give me an Atlanta hub episode two years ago....arriving and having just over one hour to get from gate at the very end of the whole airport....then making it to the exact opposite end where int’l flights take place. It took almost every minute of that hour to cover the distance...even with the subway running.