We use it frequently. Going south, there is a rest area just north of the tolls, pull in there and turn off your propane. There is plenty of parking and you can sit and relax if you care to do so.
The tunnels are only two lanes, 1 in each direction and your mirrors can pass pretty close to oncoming trucks or other RVs. If you have a problem with that, find another route or go through during lite traffic times.
I have gone thru at all different times with no problem, but lately we have set our schedule so that we arrive at the rest area around 8 or 9 PM, catch a nap and go through the tunnel about 3 or 4 in the morning. This works well for me because we continue to Emporia and this time table allows me to miss all the traffic around Virginia Beach and the Norfolk area.
I enjoy the ride going south from Jersey, I find 13 a lot more relaxing then I-95 around Washington and Baltimore.
Good luck, enjoy the views and the ride.