Why the problem with oil, you've a corn resource?? Standard Ethanol should be stand alone.
Anyway, in my shadow game, since your's in ended, I made it as far as the last part, can't remember which one.
I DEFENDED from a fort on the Hill next to the mountain chain. I actually built 2 forts, so any attacking stack would have to go alone the the level ground between the mountains. Stack in a few planes, Guerrilla 3 troops.
Diplomacy was completely different, Gandhi and Mao were the 2 biggies in mine, Gandhi actually started to beat up on Mao, who tried to call a U.N. Ceasefire, and was denied by Gandhi.
I lost or resigned in end, because I couldn't tech/build and arrive in time to beat Gandhi's Cultural Victory, and I believe he wasn't even actually trying for that victory condition.
I launched an attack way too late on Gandhi, who surprisingly had numerous defenders in a back cultural city, 1 OFF THE COAST. I landed, attacked and was wiped out by Artillery, I should have launched an attack 30 turns earlier, when I realized Culture would beat my tech.
Neil FORWARD defense with Planes, use Rails to move troops, harass, destroy, and kow toe