I'd start with the motor vehicle use map from the forest service or turn on the trail layer in OnX to see the road and ATV trail system. From the places I've gone you couldn't get very far from a road or ATV trail in the black hills, but pay attention to season closures to know what's open or closed at the time you're going. From what I've seen the deer were in pockets through out the area, so I would just pick a town or camping area to base out of and focus on the surrounding area. My first trip there turkey hunting in the spring we drove all over from North to South checking it out and would have been more productive setting up camp in one spot and learning a smaller area. There's a lot of little pieces of private land peppered throughout that seem to hold the does as well, you can drive around anytime of day and go deer watching. If you're there in the rut I would look for the doe pockets and then search the cover around that. I haven't drawn a rifle tag yet, but the turkey and archery deer tags are OTC and I've had fun on the trips I've taken, but I went in with low expectations. If it's you're first time hunting the area you might want to set your sights on one age class below the "average" you see online if you want to get something, but like pretty much any state there are honey holes that you could get lucky and find on your first try.
