Ottawasteve is exactly right.
But I think you'll be disappointed at the available payload for your Ram. That year and that trim package looks to offer between 1280 and 1480 lbs base payload (Ram Trucks - Towing & Payload
). If you've added anything, that number decreases. If you have passengers or gear in the truck, that number decreases. The fifth wheel hitch will also eat into that capacity quite a bit. So, you see your available payload dwindles quite rapidly.
Even with that Sundance being an "ultralight" fifth wheel, you're still looking at a lot of weight on the pin. The only weight I could find for that trailer was about 6800 lbs (don't know if that's dry weight, yellow sticker weight, GVWR, etc) and at 25% on the pin, that's 1700 lbs. Significantly over your truck's maximum potential payload.
Another suggestion. To get the truck's exact payload capacity remaining, take it to a scale as you would if you were taking your trailer out. Family, gear, full fuel, etc. Subtract your scale weight from the GVWR of the truck, and that's what you have left for hitch and pin weight. There is a yellow tire and loading information sticker in your driver side door jamb that will say something like "combined weight of passengers and cargo should not exceed X,XXX lbs". Also check your rear GAWR to make sure you aren't exceeding your rear axle weight rating.
I think if you do the math, I think you'll find out quickly that you either need more truck, or you need to pass on the fiver. Unfortunately, Ram 1/2 ton trucks are not really strong on payload.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!