I don't tow or own a 5th wheel. But, looking at your sketch, your driveway is 13-10 wide. If the RV you get is 8-5 wide that will pretty well take up your driveway.
Does the driveway continue back past your house so you have space for your car/truck?
I don't think you will have any problem actually backing into the driveway. I've seen 5th wheel owners back them into really tight spots.
When we bought our 96 Southwind I drew a rough sketch, to scale, to see if I could get it through a large gate into the yard.
I had to remove part of the fence.
