Welcome
Weight will be a huge deciding factor on what you can put in the back of that truck. I had a 2007 GMC 3/4 ton durmax short box, which I mainly used for hauling our 5th wheels around. Don’t overload your truck, make sure it can handle what you put on it.
I stayed away from campers with slides for two reasons. One they do fail I know I had them on my 5th wheels.
Two they add extra weight to the camper, and really, the camper is used mainly for sleeping and the odd meal prep. We do have a dry shower and bathroom, so that is also used, mostly by my wife. If your like us we spend 100% of our time outside unless weather brings us inside. So figure out what your needs will be and choose your camper with that thought in mind as well.
If your buying second hand make sure you crawl all over that thing. Up here in BC where we live there are campers everywhere and a lot of those owned by my buddies. The one thing that we always see is a small leak has occurred someplace and the camper has dry rot someplace. Look for what look like Air bubbles on the ceiling. That was most likely caused by water, if you see that run away. Push gently against the ceiling with your hands. If you hear cracking like what you get when you snap a small pice of wood, it is most likely caused by water getting on the wood and rotting it at one time. That cracking is the wood breaking, again... run.
Look at the bracket that mount the jacks to the camper, if you see different types of screws/ bolts or different sizes of those screws / bolt heads and or a lot of silicone grubbed on the bracket area, again run like heck... that usually again means water has gotten in there and the wood rotted, sooner or later there won’t be anything to screw the bolts into that hold them jacks.
Also think about storage for everything your planing on taking with you and where it will be stored in your rig. We oardered our camper from the manufacturer and ordered it with a microwave, as it takes up valuable storage space.
Also your going to have downsize on what you take. Now it is just me and my wife, camping so we only have enough plates, cups, glasses etc for the two of us. We have it so all that stuff is in a drawer, not the cupboard. We use the space where the microwave should have been plus the cupboard where most people keep there plates, cups and glasses for our food.
We did a lot of research and planing before we changed from a 35 ft 5th wheel to a 9ft floor or a camper, and we have never regretted the change.
Have fun and read read read...
Soup.