Having fequented a lot of national forest remote places that have to be reached by logging roads, plus a few where I just had to make do, only had one bad place where the camper bottomed out (and should never had been on that road in the first place).  Unless really doing some serious off-roading, I'm inclined to think the standard height of a straight axle/leaf spring suspension is adequate. How the trailer tows on the main highway to and from the camping area is more important. Quite often modifying the trailer height is done to level with the tow vehicle.

Here's a Dexter website for modifying trailer height ~

http://i.b5z.net/i/u/1080235/f.....stment.pdf