I came close to buying a Lance, I wanted a Bigfoot or Alpenlite but no dealers for those two in my immediate area. I looked at the Alpenlites at a dealer near Austin, was not impressed with their build quality. I found much to my surprise there was actually a Bigfoot dealer near Dallas (Ed's Camperland in Waxahachie) he brought in a 2500 series for me to look at and WOW! it was slick. Not much more expensive than the Lances I had seen, but still too rich for my blood.
We have a big Lance dealer nearby, and I have been over their campers with a fine-tooth comb many times. Build quality is pretty good, design is excellent and well proven. I eventually decided to buy a used Bigfoot, as I had heard many horror stories of rotted truck campers with pinhole leaks and wood frames. After more research though, I think the rot problem is not as big an issue as I originally thought - just get something like Eternabond tape and seal all the seams, make sure windows and roof penetrations are taped good, and no worries. I wouldn't be worried at all about buying a Lance with wood frame now, I'd just seal the heck out of it on delivery. (Would be very, very careful about buying ANY used wood-framed camper though).
I took a trip to the Wichita Mountains Wildlife Refuge last weekend with the Boy Scouts and while we were there I saw a couple of guys with Lance campers out having fun. They were the smaller versions (820 as I recall) but quite nice, one of them had a dog along. They seemed to be having a ball, and as we don't see a lot of truck campers in use in our neck of the woods the boys got a big kick out of the setup and how the truck was parked in a regular space. (The Scouts haven't seen my Bigfoot camper, when we go camping with the Boy Scouts it is tent city)
Tell your Dad to find a nice camper with weight matched to the truck's capabilities, seal the seams good, and just get out and have FUN. He'll have a ball with the rig, they are so much fun and very practical to boot!