Tunnel clearance is missleading as the tunnel is arched and posted clearance is not in the middle, I have seen large RV's travel through it but we opted not to try in in our 40 ft HR that tops out at 13'5. Easy entrance is at Swift Run Gap (MP65 or so) near Harrisonburg or if comming from further south the entrance off I- 64 at Rockfish Gap (MP96). Traveling north to Big Meadows at Mp 50 is best bet for camping. Campground can handle largest of coaches. Travel along the drive in RV is not a problem as speeds are low and large trucks service the lodges at Big Meadows and Skyland which seems to help keep overhead branches clear. Great overlooks of valleys both on east and west sides of drive. Most popular areas are between tunnel and Swift Run son not too big a deal if you can't clear the tunnel. Restaraunt at Big Meadows is a bit better than the one at skyland. hiking to Soney Man Mountain, Hawksbill and Dark Hollow Falls are a must. Spend time watching wildlife in the Meadows. Black bear sitings are common so food storage precautions are in affect. No hook ups but water is generally close. Campstore is also avilable at Waystation next to vistors center. Good starting point for overview and history of the park. Enjoy!!