Take a look at the sticker on the drivers side door pillar. It will tell you the carrying capacity of that truck. Its very doubtful that Ram has more than 1200 lbs, and I've seen some decked out 1/2T hemi Ram's with less than 1000 lbs.
I was quite surprised when my brother-in-law brought over his new-to-him 2015 F-150 last week. Its a XLT supercab with 6.5" bed and the 5.0 V-8, and not much anything else, basically a stripped XLT. The carrying capacity was over 2200 lbs. I've seen some 3/4T pickups with less than that. My 2011 F-150 is 1400-something.
A newer 1/2T Ram is not a good choice for a truck camper. You'll be over your GVWR, over your GAWR, over your stock passenger tires weight rating, and since the truck camper doesn't have its own brakes, your stopping power will be greatly diminished. Like others have suggested, a light travel trailer should work well for you though.