I run a winch on my Jeep TJ and it gets used a lot, but having a decent amount of experience with a winch I can say I wouldn't bother with one on my truck camper. To get one sufficiently rated and good enough quality that you can rely on it that one time you need it means spending quite a bit of money and adding a load of weight.
I disagree that it takes a tremendous amount of winch on a truck camper. I have an under rated 9,000# winch on my rig. The mount and winch only weighs about 80lbs. No it won't get me out if I'm buried to the frame in mud, but it sure will get me out of most oops I'll find myself in with a camper on the back. It definitely would have gotten him out of the sand if he had something to attach to or could bury his spare as an anchor - of course so would have 4wd.
I use to run the same winch on a 4,000# jeep on the trails so know what it takes on the extreme stuff, but generally we aren't talking that type of "stuck" when in a truck camper. The 1-1/2 times the weight rule doesn't apply.