A couple of shopping questions

Unless you go for most basic TC without a slide, expect to be over your GVWR. Most campers with a slide will be about 4000 lbs once you load supplies and water.

Your biggest limit on the truck are the tires and rims, so you will want to measure the weight on the rear axle empty to get an idea of how heavy you can go without upgrading to 19.5" wheels.

Without the camper package, your truck does not have a rear stabilizer bar - Look into Hellwig's BigWig. The suspension will most likely compress enough that the rear will sag - Adding TorkLift upper and lower StableLoads will allow you to carry most reasonably sized TC's with out the need for air bags.

You will need remove any plastic bed liner you are using but in a thin rubber mat - This is the bottom of the TC does not slide around. My preference is for the frame mounted tiedowns made by Torklift, but some people are happy with the body mounted HappiJack.

A short bed camper will have the same COG in a long bed or short bed, but there will be a gap between the camper and cab if you use a short bed camper. SOme people do not like this while others use it for external storage.

I'm sure you will have more questions, but this will get you thinking...

Most people say allow 1000-1500 lbs for what you carry. Also, Fords typically come with a Ford recommended truck camper weight. For yours, it is probably around 3000.

There is no rule of thumb. In fact it is very rare that a TC does not exceed the factory payload rating of the truck carrying it.

If you come anywhere near your truck's payload capacity, you will usually feel the need for some sort of suspension help regardless. This is to reduce the rear end sag that you normally wouldn't worry about if you were, for example, hauling a pallet of cinder blocks to the job site.

What many people do is go by the axle weight ratings of the truck. That's usually limited by tires on the rear axle, so if someone is wanting more, they simply upgrade the tires and add more suspension modifications.

So in a nutshell the ratings don't mean a thing. Just do what feels good, and if it don't feel good, throw parts at it.

I'm one of those rare occurrences where I'm not exceeding any rating on my truck. By a lot. Not by choice, necessarily. I was looking for a 2500HD truck, and this one fell in my lap. I was looking for a larger hard side camper, and this one fell in my lap. Been running this rig for 5 years and it does the job. I'm not fussy, and when I'm not camping the truck will tow or haul just about anything.

Bedlam wrote:
~snip~
A short bed camper will have the same COG in a long bed or short bed, but there will be a gap between the camper and cab if you use a short bed camper. SOme people do not like this while others use it for external storage.
...

Bedlam is correct. COG relative to the rear bumper is the same regardless of a short bed or long bed camper- my COG is about 2" forward of the rear axle- same as on a short bed truck. I am doing the SB camper on a LB truck... that extra space is welcome for storage and for my generator:





I built a simple frame to place between the front of the camper and the truck bulkhead. It is custom fit to keep my generator in place.

Alrighty, looks like I need to look for something way under my payload and allow $1,500 for Stableloads and other suspension bits.

Basically most campers that are 9' or less long are considered short bed campers, but a lot of them will fit all the way forward in a long bed, unlike the pic above. If they have storage or a generator mounted down in the wing/overhang area then they may be "short bed only" or sit back like the pic above.
Bottom line, anything from a pop up to a double slide 11' camper will fit in the back of the truck. Depends what your "must have" features are, and what the wife will live with, lol!
Many variables in what a person is comfortable with hauling.
I'd recommend finding a couple you think you like and get the "real world" weights from a forum like this and experiences/mods required to haul it.
I wouldn't have had a clue what my camper weighed before buying it based on the stated weight online and on the vin tag without researching it here

d3500, that is a great storage solution! Beats the hitch carrier I hauled all over the country!