I'm also in Atlanta. What I've found to work very well is a plain vehicle with a trunk...AKA hide everything so others won't see it. Its nice to do work and then throw everything in the trunk then stop somewhere for a bite, knowing the average bum isn't going to see anything in my car...let alone even consider it with a Lexus sitting next to it.
Smaller is better. Lets be honest, what all are you carrying? On average, I carry a backpack, a camera case, a tripod, and some light stands. Yep, fits in the trunk with plenty of room to spare for cooler, jackets, etc. All of a sudden in a cramped parking lot or a narrow parking deck, the little car starts to shine. On top of that, parallel parking is better and then there is better mpg since the smaller engine doesn't use as much during idle.
That said, I've always used a boring sedan for my off road work. The older, the better. Typically when I do work outside of the city, there are others that are the focus of my lens. So I let them do the driving and I jump shotgun. The car sits at the staging area, with the backup gear stored in the trunk so no one knows its there. When people pull up, they look at it and think someone has left it there to ride. Not "oh I bet there is $5k in gear in the trunk. Where did I put my screwdriver again!!??" Not having a vehicle on the trail is 45986730443x better because now I'm not worried about my vehicle, only my subjects vehicle. I'm not worried if its built enough or breakage or what its doing. During the shoot, I am focused on my subject. Any obstacle or location I would want to be at, I'd catch a ride to that location.
On top of that, after I traverse the 50 ft of dirt road, the sedan shines on the paved roads. Even that little bit of dirt road, I've only had an issue ONCE when I was parking on a hill on grass and it was pouring rain. My bald little tires weren't doing a lot. Fortunately I was able to back up and head downhill some back to the road. Just pre-planning on my parking spot was just as good as 4WD and mud tires, however the 5 hour drive home was much more enjoyable. Oh and I did scrape the bottom on a whoop-de-doo once. The next one I took it at an angle with decent momentum. Lifted some tires but it didn't matter.
I've used my personal 4WD for TWO shoots. One, I knew I was going to be in a remote spot on a closed off road race course so it was nice having my personal vehicle with the cooler, etc right there. In hindsight, I could've caught rides in and out but I wanted to take my personal 4WD. It was nice having it but not necessary. The second was a choice, mainly because I wanted to go wheeling where the shoot was.
In terms of plugs and whatnot, I've only had an issue twice were I had to go back to the car to resupply. Basically, for both situations if I had decent memory cards then it wouldn't have been an issue. However I was trying to be a cheapo and I paid for it. Also both events were WEROCK so you literally are shooting 4 fps (I mean, you can shoot more than that but that seems to work best for off roading) the entire day. Memory cards fill up fast like that. However the last few shoots I've done, I've filled one 8 gig and most of a second, leaving a 3rd in reserve along with my fleet of smaller cards. Batteries, I carry a spare but typically I have them fully charged before getting in the field. I've never had to recharge in the field. However my setup is all battery based (strobes with spare batteries) so with full charges, I'm typically good to go for all day.
You probably know all of this but I just thought I would throw this out there that despite doing tons of off road work, I drive a $1000 front wheel drive sedan with street tires out there.
If you want to do landscape type of work, in all honesty a Subaru Outback can get you 98% of the forest roads in Georgia, South Carolina, and Alabama, no problem. The extra traction of the AWD and being higher off the ground will help in the few tight spots. However I've driven a significant number of them with my sedan as well and haven't ever scraped. There are a few places that such a vehicle won't cut it but to actually access the area you want to be in is a few hundred yards away. A good set of boots fixes that problem.
Dunno, just trying to provide a more "basic" point of view on the subject.