Just to share my experience, as I currently running a shop + track in Brisbane, Australia. I have both indoor on road and out door offroad.
We use asphalt as the indoor on road surface, as it is grippy, and not much maintiance needed after we lay them down, the key is to have a good track system.
For the out door offroad, we used clay, pure clay, which gives good sufrace traction, but require more after work to keep them in good shape.
I have post some pics on our site www.hobbystation.com.au
when we did the laying of the asphalt, took half a day, and can put into use 2 days afterward.
Hope this help