Dry tongue weight versus fully loaded

Whatever makes you comfortable I suppose. But for the record buying the Denali is a placebo for “comfort” unless you’re only comparing seats. 
I can guarantee you they have the same suspension as so called mid range models. And it’s just as easy to ballast the bed and drop tire pressure on any truck. 
Not sure what you mean “buy a scale”. You’re talking over $1000 for Chinesuim Amazon scale on up in price. 
^This is laughable. Whadaya doo if you go thru all that and find a weight you “don’t like” even though you don’t know what that is yet?  Scrap it and buy a new camper?  
If you’re weight paranoid it’s a connundrum. You won’t know exactly what you got until after you buy it (even though “exact” doesn’t matter real world) and once you do, then what? Hand wringing on down the road?  Make the wife unpack half her stuff? Buy a Dooley?  Get a lighter camper?

Im being semi dramatic for effect to help you realize either your worrying about nothing or you just maybe should stick to 4 wheels if you can’t get over it. Being honest. 

Thanks for this great input. I’ve been trying to find sources of information without a lot of success until now.  Regarding the door, we’re looking at one of the Northwoods 27 foot fifth wheels. The specs aren’t listed but copilot AI believes that the door is 36 inches wide by 84 tall and the deck height is 24 inches off the ground.  All of those specs would work just fine using the ramp. I have to get her chair through the door.  (if copilot knows what it’s talking about.)

Regarding the choice of truck taking a little closer inspection I think I’m gonna need the 3500!  Problem comes in the payload, even with the max towing package. If my wife and I brought along two friends (that have much weight to them at all., a GMC 2500 hd with max towing would already be overweight without any other gear in the truck, even if using the 22% pin weight calculation.  This is surprising to me.  

Regarding the toy haulers, I’m not sure what the ramp slope ratio is, typically 2 : 12 is recommended for safe use with wheelchairs.  I have been able to carry the chair in my tundra which has a slight lift on it with the bed about 32 inches off the ground using a 10 foot ramp which is a little bit on the steep side, but if the chair is empty, I can drive it up standing next to the chair successfully. Even at that the ground needs to be totally flat just a slight pitch throws the angles off and the chair can start sliding down the ramp when you drive it out of the bed.  Need to be real careful with these chairs to avoid 450 pounds crashing to the ground off the side of a wheelchair ramp.  The 24 inch deck height on the North woods trailer, as long as that door is big enough, would be no problem at all for my ramp.  

As noted, some will tell you to ignore the specs... there is some truth but it's gotten more complicated in recent years as 3/4 tons have gotten different suspension systems. In the old days it was often just the springs but not today.

But if buying a new truck, just get one that is in spec...why go thru the hassle of overloading and then having to upgrade the suspension... when buying almost no difference to upgrade to a suitable truck. If you have the truck already, then it becomes a discussion if you can upgrade the truck.

Opening the cargo door takes 30 sec when we had one. Only issue would be making sure you don't back up to a tree or drop-off. 

I'm very much unclear how the OP is getting a 450lb chair in the side door.

So what is the answer when we can't take his fully loaded new camper to a CAT scale to get real numbers before buying the truck and camper?

If you can't get real world numbers best to assume a little on the conservative side, so you don't find yourself overloaded after you've spent a lot of money. Assuming 25% of the gvwr is a safe initial assumption.