Two points:
First: if you're suffering a rough ride on an unimproved road that allows conventional driving speeds, the problem isn't solvable by "airing down"; sure, you'll mask the symptoms, but the rough ride will still be present. A rough ride is solvable, however, by adjusting tire pressure - and yes, that's different than airing down, for those that don't know - and by selecting a shock that's set up well for the vehicle at both low and high speeds. Also, look to the seats: if they're old and crushed, you'll get a lot of harsh jolts right in the lower back...and that gets a bit tiresome after a few hours.
Second: when you air down, disconnect the swaybar and travel long distances, the strain on the drivetrain is immense. The rolling resistance of the tires goes up sharply, which causes almost every major system on the vehicle to work harder: tires, engine, transmission, t-case, differentials, shocks and springs will all see a greatly increased load because the tires are floating and gripping more than they're rolling over/through terrain that doesn't require that kind of traction, and because the vehicle will be swaying all over the place without a swaybar to reign it in. None of those things are good when you're putting mile after mile on the odometer.
Again, if you reach a spot that can't be easily traversed and you have to crawl it, drop the air pressure and/or disconnect if that's what it takes...but don't do it until you have to. Match the vehicle setup to the terrain at hand, and beware of blanket solutions.