Paul is ABSOLUTEY correct on this one. I was going to wait on the "Brakes/Weight" lecture until more info on the camper was attained, but I'll go into it now.

Is there a rating plate on the camper that gives the "empty" weight? If not, you might see if your friend would be willing to put the camper back in his truck, get the whole rig weighed, then remove the camper and weigh the truck without it. This'll give you a base weight for the camper, and can give you an idea on how much truck you NEED.

IMHO, on something like this, the larger of a truck you have, the better, but it's best to know what to look for. There should be a rating plate (or a sticker) on the truck somewhere, usually on the driver's side doorjamb, that will tell you what the legal maximum allowed weight on the truck can be. Note that this weight is not so much based on engine power as it is based on spring and, more importantly, brake capacity. If your vehicle goes over this weight and you get into an accident due to anything related to an inability to brake or anything to that effect, you can be in a heap of legal trouble. Take a look here for a somewhat extreme example of what I'm talking about.

Okay, here endeth my lecture on why you shouldn't skimp on the truck you buy to haul this camper around in. Now, to figure out which truck to get. On the rating plate, there should be three numbers available. These numbers are:
GVWR: Gross Vehicle Weight Rating
GAWR Front: Gross Axle Weight Rating, for the front axle
GAWR Rear: Gross Axle Weight Rating, for the rear axle
The GVWR is, simply put, the maximum weight that the entire truck is allowed to weigh. This weight includes passengers, the camper, any tools you carry, a full tank of fuel, engine, transmission, truck body, the whole 9 yards. This does not, however, include a trailer (except for the tongue weight).
The GAWR is the maximum weight allowed on the respective axle.

It is possible to exceed one number without exceeding another. For instance, my F-250's GVWR is 8600 lbs, the Front GAWR is 4410 lbs, and the Rear GAWR is 5873 lbs. If I loaded my truck so that there was 5800 lbs on the rear axle and 3000 lbs on the front axle, neither GAWR is exceeded. BUT...it puts me 200 lbs over my GVWR, and I'm therefore illegal. Likewise, if I loaded my truck so that there was 2000 lbs on the front axle (which, on my nose-heavy truck, is almost no weight beyond an empty truck) and 6200 lbs on the rear axle, I'm below my GVWR, but my Rear GAWR is exceeded considerably, and I'm just as illegal.

I don't know if it's possible to determine the GAWR's from just knowing the truck's GVWR and the weight of the camper, so you're probably best off getting some base numbers from your friend's truck, use that as a basic guideline on what truck to get, then once you get your own truck, get it weighed with the camper and you can go from there on arranging things, knowing how much you can safely carry (luggage, toys), etc.

This all said, unless the camper's a monster and/or you're also planning on hauling a trailer (a second camper trailer, a boat, an ATV trailer, etc), you're PROBABLY safe with any 1 ton dualie out there. If the camper's huge and you also want to haul a trailer, I'd think long and hard about a small medium-duty truck, such as an F-450. If the camper's on the small side and you're not planning on hauling anything else, a 3/4 ton may or may not be safe...again, it'll be easier to tell once you have the camper's weight.

Sorry for the long-windedness here, but there are a lot of RV'ers out there who are dangerously overloaded and don't even know it. For instance, a sizeable portion of 5th wheel haulers should really have F-450's instead of -350's. I wanted to at least make sure you were aware of the issues.

As for brand preferences...that's a whole different ballgame. Most weight capacities are similar enough that it won't make or break a single brand from being a choice. A 4x4 would be to your advantage from a resale value standpoint...although there's a bit of a weight carrying capacity sacrifice due to the extra weight associated with the front drivetrain, and depending on where you're camping, it may be something you'll never use (conversely, it might be something you use every time ). As mentioned, I'd recommend a diesel engine, from a reliability, longevity, and economy standpoint (conservative driving could probably get you 14 to 15 mpg with the camper, whereas a g@$ engine would be lucky to get into double digits). Also, from a longevity standpoint, I'd recommend a manual transmission if you're willing/able to drive one.

Again, from a brand standpoint, my first recommendation would be Dodge, with a 7.3l-powered Ford as a close second. The Cummins engine has longevity in its favor, although the 7.3l drives a bit more like a car (V-8 powerband as opposed to that of a straight-6). The 6.0l is even more car-like, but early engines are plagued with problems, and it's still up in the air as to whether or not Ford has really fixed anything. I would avoid GM like the plague, although that's due to a strong aversion to aluminum-head engines and IFS 4x4 front ends.

Just my $.02...I hope this helps some