You spoke of trailer tongue distance. Keep in mind; when you go over driveway entrances, like at a gas station, the truck with camper will dip the back end while the boat will be still 'UP' on the street. This could cause an interference issue between the bottom of the camper and the top of the trailer's tongue that's up under the camper.
Try to plan what ever length hitch extension you will need so the ball is just past the rear of the camper. That is for two reasons; the first I just explained, but if it's close to the rear, the trailer tongue probably won't interfere. The second reason is that the ball height, in order to keep the trailer parallel to the ground. level as they say, might not allow enough clearance between the top of the ball and the bottom of the camper for you to hitch up the trailer. At least, not without using the jacks to lift the camper to gain the clearance needed.
Just something to think about.
If you do use an extension, I highly recommend using chains with turnbuckles so you can tighten up the extension. That little movement at the receiver is amplified from a little wiggle to a few inches when it's projected 2 or 3 feet out. Add to that, the ball mount will also have wiggle. Without tensioned chains to stake out the extension, you will get so much movement, that again, if the ball is under the camper, it could hit.
BTW, I'm over in Placerville, about an hour from Rocklin. I have a short bed Dodge with a Lance 855S 8'11" camper and I flat tow a Suzuki Samurai 4x4 behind it. I'd be happy to have you come over and see how I set up my tow extension, my safety chains, lighting, trailer brakes, etc so you get an idea of what all you'll need to set up towing with a camper on. Lots of little parts like receiver pins, wiring extensions, various clearances, etc are all details that took me several trips to work out. I spent several afternoons with the camper, the truck and the towed working out the angles, the leverages, the wiring, etc. I'd be happy to pass what I learned along over a beer or two. BTW, got a couple other camper guys who tow as well living very close by and I'm sure they'd be happy to drink beer and pass along their combined knowledge as well!