Actually to go scouting you have to have your base permit. So to answer your question, as soon as you want to get out there and scout you can get your permit and safety stuff out of the way.
There are trees well worthy of stands. 90% of the folks there hunt out of treestands. You will not have any problem finding a tree for your stands.
Most of the base is the same. Rolling hills mixed with ravines and valleys, swamps, food plots and power lines. I would concentrate on the oak flats for the scouting purposes. From the oak flats you can actually see the trails and such leading to and from the bedding areas. The base is borken up into 31 TA' s (Training Areas). Not all are open at the same time. I would make several scouting trips to the base and select two areas on each trip and go out and walk them. It took me 8 years to get a real handle on almost all of the areas on post. It takes a while but I would do two areas per trip. You will get a feel for the areas and you will be able to locate draws and flats, bedding areas and water sources.
There are all types of habitats for the deer from swamps to food plots. There are open oaks and pine/laurel choked thickets. I would start out on the NW side of 301. That is the side with the GCS, BTW, it is easy to find.
http://www.aphill.army.mil/hillmap.asp
This is a link to the basse that shows how the base is broken up into it' s 31 areas. The game check station is locate in area 23 right on the main strip, aptly named " AP hIll drive" . It is located about 1/2 mile beyond base housing.
There are tons of deer in all the areas, I would start scouting in 7,11,12,15,18, 20,21. They are all very productive areas and will give you a chance of harvesting good deer.
I get my aerial photos and topo maps from the following site
http://terraserver.microsoft.com/ima...=1318&z=18&w=2