I was thinking of doing something similar to this, only it took place in a futuristic settings, sort of like HL2 only there was no invaders, just a corrupt government regime and a resistance group, the difference in the RP is that a TDM stage is set up, with actual straight up combat rather than playing against AI, and then after the battles, they would have the RP the difficulties of before and after battles and the in-betweens. i tried to start the resistance base being in a train yard but eventually stopped.