I've lived in the Pittsburgh area all my life and operated big trucks all over and in town. Now there are interstates into, out of and in Pittsburgh. All bridges, tunnels, overpasses are over 13'6" so no problem. AGH is on the old truck route of RT. 19 before I-79 was built. From the east or south exit off the I-279 onto 10th St. then turn left onto the 9th street bridge and go up to AGH. There is no place to park your RV there but you can take your toad.
The problem with campgrounds is the same with truckstops. No one can afford the high taxes to operate a high end large acreage facility. You will have to find a campground out of the urban/suburban sprawl outside the 50 mile radius of town. Don't be afraid of taking your motorhome through town. The truck routes are clearly marked and will keep you out of trouble.