I've been doing this for over 8 years now. 2000 Fleetwood Tioga 23b/Crownline 180BR(3,200lbs). Easy peasy. The Ford 6.8 litre pulls the boat fine at highway speeds. With 7' from the rear axle to the trailer tongue, backing is easier than with a pickup truck. I prefer to launch the boat by myself without any help. My wife/kid/friends will help me prep the boat for launch, then get out of the way as I have found them, while good intentions, to be a distraction. At times, when I launch at a ramp with multiple lanes, I get people taking photos/videos. While their boyfriends and/or husbands are pulling forward for the 8th time to straighten out there $60k truck and $80k boat, I am in, float the boat off the trailer, a quick tie off to the pier (yes you need a pier if launching solo), and off to the parking lot. All while the pickups are still trying to launch.
Key is don't let your back tires touch the water if the ramp has algae under the waterline. I have found the steeper the ramp, the easier to launch as the boat floats off the trailer sooner. At no time in my rear bumper, never mind my "cabinets" are close to the water . I wish I had the 4WD (6WD?) version of of my 23b model RV, but they are hard to find, and a little pricey.
So yes, it is doable. Take your time backing. Keep the front widows open for a quick egress if necessary(that goes for ALL vehicles on the ramp). And keep your back wheels out of the water. Have fun and stay safe.
Oh, and another option. My father installed a receiver on the front of his class "C" years ago that worked very well. He would unhook the boat trailer, spin the RV around and hook up using the front ball. This way, it was easy to "back down" the ramp, and his rear tires were nowhere near the water.
I hope this helped a little. Have fun and stay safe.
Al