Since I live in Las Vegas, I don't have a dew problem. A dust problem, yeah, but dew, no. My commercial Dob sits in its place in the garage, stacked and ready to go. My home-built Dob used to sit there, taking up twice the space. Now, that home-built scope sits in my storage shed in the back yard, buried under scrap wood and yard tools.
I keep the optics covered to at least keep some of the dust off, though a little creeps in no matter how careful you are. As for anything else, it's not an issue. Temp wise, they cook in the severe heat but then again, they acclimate pretty fast when I throw them in the truck for a night out at the observing site. The OTA of the commercial scope goes in the air conditioned cab if it's summer, the heated cab if it's winter. If we're going on a long trip, it sits in the back bed with the mount and the ice chest and everything else. Basically, it's just "moderately delicate luggage" until I'm ready to set it up.
Oh, and I learned a long time ago to put duct tape on the collimation knobs. They have a tendency to back out on those bumpy roads!
Another thing. I'm a woodworker, so being in the garage, the scope is exposed to a lot of sawdust besides regular dust. My optics still stay clean for years. Those covers work wonders.