The FWC is very, very rugged. If you really want to go offroad, that could be an advantage.
If and how much offroading you really want to do with a fullsize, crew cab truck with any type of TC in the back, you will need to find out for yourself. Member jefe4x4 offroads with a conventional Lance hardwall camper, so it can be done. But I have also seen pictures of a stripped tiedown anchor on a popup camper on this very forum.
Back in 2012, I visited Hallmark and Outfitter. I was impressed with Hallmark as a company, and I liked the product. I believe they give you a choice of wood, aluminum or Coosa for the frame. I like their campers, and the build quality I saw at the time was very good.
I had an Outfitter Apex 8 myself. It is a very well thought out design. Build quality was somewhat mediocre, but it was a great camper and it held up well. I had it on a Silverado 2500 single cab, long bed gasser. Even without any modifications, the truck handled the camper very well. Although they are on the heavy side for a popup, the cog is very low, which helps with handling.
The camper worked well in freezing temperatures (-5 Celsius), but with the aluminum frame you needed to watch for condensation.
Re. towing with a hitch extension: why else would you have one? As long as everything is within specification, where would there be a problem?
