Hooking and unhooking?

Our 5er at home when disconnected ( and level) is about a foot above the truck hitch. When I back the truck up the hill to hook up, the truck is not level side to side either. Once the truck bed is near the pin, I lower the 5er and once lined up I back right in. The hitch will pivot in any direction to line up. The real issue for me is to make sure the pin plate ends up flush (flat) on the hitch plate. The more I do it, the easier it gets.

Chock trailer wheels well. Maintain truck pressure back against the hitch to open/ close the hitch jaws.
Measure your trucks unloaded hitch height, cut a 1 x 2 stick that length, with marks on it for truck wheelwell height when unhooking trailer, use trailer landing jacks until those marks match ( load off), use it to get the trailer pin just right when hooking up. And mark your slide widths on it so you can be certain of clearance.

Thanks for your early posts already. My truck is a 2000 F 350 4X4 Supercab long box, and the rig is a full size 2009 fifth wheel.

I am not really steep like some, it's just sloped not steep by any standard.

Hard to say without looking at the driveway. It can be done under most circumstances. One time I had to pull a couple of pins and pull my head off of hitch base, then released head from trailer pin box. I bought a B&W hitch and feel it will work as well as any. They make one thats real easy to just pull a pin and leave the entire hitch on trailer pin box, and truck bed free of hitch.

Another issue is roll, if the truck or trailer "roll", and the other vehicle doesn't (it only takes a fraction of an inch) the wrong way, the king-pin and be a little bound against the mechanism that you need to release the king-pin.
Normally all you have to do is put the landing gear down, start the truck and put the transmission from park to neutral and back to park.
I see this most often when say the trailer is level and the truck is slightly pitched.
I also see this more often with my PullRite then I did with a fixed hitch
Under the worst case I have to un-pin the hitch head from the truck and use the landing gear to raise the head off the truck, this finally releases enough tension on the king-pin.

Oh, ya, I think to off-straight number for the PullRite is 15degrees.

The pivot head on the hitch will probably adjust to the angle ok. The issue may be about how much bed rail to the underside of the 5er clearance you have. Some new trucks sit real high. If the 5er is sitting low there may be interference. That brings up another issue which is how high your truck is to the 5er even when it's on level ground. Some 5er and TT require spring/axle flips or other tricks to raise them to level with the truck. You need to look into all that as you consider what to buy. High truck/low 5er = modifications.

If you use an auto slider hitch like Pullrite, the 5er will need a capture plate. Because of the capture plate "key" type area that has to match up with the hitch plate grove you need to be within 10 degrees of straight. I may be off but I think it's 10.

If you can unhook it without any binding, then hooking it won't be a problem. The hitch head will tilt front to rear as well as side to side. The only issue with backing at an offset is your truck tailgate. Depends on the clearance when your gate is down. Some fifth wheels have more clearance than others.