I think I am the 'jeff' mentioned above. my friends call me jefe (Hay'-fay). If you control the sway and add some suspension help on the back, you should be O.K. with a hard side. Since you live in So. Cal, my advice is to get a pop up camper. It will glide under the trees easier and have a slightly lower COG, compared to a hard side. A hard side will be taller, quieter, warmer, maybe heavier, and better equipped to take on long trips, off-season. My Dodge has a 3" lift, which I think would translate to a 6" lift on a Chevy, as they sit pretty low to start with: front and rear with 8 leaves on the back (3 are upper secondaries, or overloads) There is a thicker helper down low in the pack which works great when the rig is MT. Down at the end you can see the Jet Black Stable Load block:
You know, after looking at the pic above again, I should just cut and chamfer the lower overload springs down to about 10" long as the suspension will never, ever flatten enough to bottom out on the thick overload.
A lot depends on which rear end you have. Is it an 11.5 AAM? If so, you can massage the suspension to keep the rig flat. Do you have the upper secondary or overload springs? I hope so. If not, use lower Stable Loads. My Chevy 2 series buddies swear by them. More leaves. Thicker anti-sway bar. Hairier shocks. For you, maybe double adjustable shocks on the rear. Air bags (which i do not recommend because of the recoil) Timbrens. Stable Loads. Mine work fine. My little Lance weighs around 1845 pounds, wet, and loads up to around 2680 pounds. I use 15.5" wide super singles on the back, on 12" wide rims to spread the load wider with less ground pressure (good for sand) and work the tire pressure to be appropriate for the terra I'm rolling on.
Look for my trip report above on Death Valley. There are some tire pressure talks in there. In the end, very few truck camper people adhere to the printed, factory specs on loading for very long before they start the inexorable climb to a more capable place with the suspension, with or without the sanction of the Big 3 Lawyers. I'd keep the lift but do a lot more suspension work.
regards, jefe