Super Basic Questions

Get the long bed. A short bed can carry that camper but a longbed does it better and doesn’t restrict you to only ever having a really short camper.

Sorry it's a 2002 Model 811, so there weren't two versions.

811 Comes in two versions. Short bed version gets a generator and more external storage. Long bed version has less external storage and can fit both short and long bed trucks.

I have a 3500 short box 4x4 duramax with a Northern Lite 8-11 on the back. I put 42,000 kms on the truck and camper the first year ( Sept 2017 - Sept 2018 ) we owned both. I have also owned many different types of rigs over the years.
We spent over two months at BLM land in Southern Arizona during the winter of 2018, no issue at all in a short box type camper.
We also spend 90% of our time outside the camper so inside comfort is great, however not something that we based our buying this camper on. Don’t get me wrong, the camper came with TV / DVD / stereo, a stove and oven for cooking a huge fridge and a dry bath, built in solar, so all that stuff is nice and is found in most rigs you can buy now. ( different manufacturers have different options)
I have no issues with handeling or ride in all those Kms, I did add Timbren rubber overload springs.
We dont have a slide, never wanted one as more weight and more things to break.
The basement on the Northern Light where the Gray and Black tanks are located in the floor and you can’t accees them unless you remove the floor inside the camper.
The basement in our Northern Light has a 12” x 36” x 6” high storage area, as well as a 14” x 84” x 5” high plastic slide tray right beside the other storage area. It also has a storage space for a 2000 watt Honda or Yamaha generator ( we have a Yami)
As for resale value... I worked with contractors all my life in the profession I was in, and they use both short bed and long bed trucks equally, unless they are fleet trucks then they aren’t buying from a single seller anyways.
The one thing I would make sure when I bought my truck was a crew cab truck. As we use that extra space in the back seat as storage ( lawnchairs, water jugs, tables, Tools..etc..)
As there is only my DW and myself that travel in our rig, and Gertty the cat rides in the camper... ( grin) that backseats is a perfect storage area.
So a long box truck and camper would be nice to have but not necessary.
My twobits
Soup

All good points, save for the resale value comment and ride.
If one hasn’t noticed, short bed trucks are probably more numerous than long bed. The demand is the same for both. Not an economic decision factor.
And ride.... how long of a wheelbase do you need? Today’s ccsb trucks are longer than pretty much every truck from 20 years ago when most were single or ext cab. Plus, if your camper is taking significant weight off the front axle , you’re doing it wrong. I haul the biggest heaviest camper you can stuff in a short bed, with basically zero regard to what we pack in it or weight distribution and pre trip it puts a little weight on the front axle. Post trip and towing it takes some off and there’s not a lick of difference in handling. If anything matching the trailer to the back makes it handle better in turns and wind, which is strange but the tongue weight seems to stabilize more.
Bottom line, one can be super finicky about all this stuff or you can load your camper and go camping. Take your pick.

If you start off with a short bed truck/camper combo and then in the future decide you want a bigger camper - well then you will wish you had bought a long bed. Something to think about.

I would strongly recommend a long bed truck for a TC. It gives more support under the camper. A longer wheelbase will ride better. Long bed trucks usually have larger fuel tanks than short bed trucks. A 3500 long bed will likely have better resale value as it will appeal more to tradesman looking for a used work truck.

Ohhhhh, so that's what they mean by "no raised floor"....so there is no basement! There are no "wings" on the back of the camper, so it would slide all the way into an 8' bed. From what I've been reading, it seems like the longer bed is the way to go since you can get more weight ahead of the axle, plus not have to worry about overhand for towing etc.

I may be wrong, but here is my take. Remember, advice on the web may just be worth what you paid for it ;-)

The 811 was the shortest Lance camper with a slideout at the time, with a floor length of just 8'6".
Technically, it should fit on either long or short bed trucks; my preference would be a long bed. The sales brochure doesn't seem to specify the required bed size.

But it says that they are proud of the low profile of these campers. I am not sure if they even have a basement. From the pictures I have looked at, I think not. Somebody please correct me if I am wrong.

Lance gives you access to historic brochures and manuals; go and look for yourself:
https://www.lancecamper.com/ -> Owner Support

An 811 will fit in either a shortbed or long bed, unless it happens to be a shortbed only model (rear "wings" have storage compartments or generator etc preventing it from sliding all the way fwd in a longbed).
If its a shortbed model it can still be carried in a long bed but will have a large gap between bed and cab. Looks goofy but provides more storage space at the expense of rear axle weight.