We tow a 2013 4×4 F150 4 door and it works fine, no problems. Very easy to get ready for towing. There is a dial on the dashboard that I have to turn from 2 wheel drive to 4 wheel drive and back again to 2 wheel drive 5 times in 7 seconds or so and that puts the transfer case into neutral. The key does have to be left in the ignition and the transmission is left in neutral.
Check the owners manual for instructions on flat towing behind an RV. Make sure your model can be flat towed. I have made a rule to check the owners manual before I actually buy the vehicle to make sure the owners manual supports flat towing. Your tow bar needs to be rated for over 5000 lbs. Our truck is about 6300 lbs.