hey guys this trophy sounds hard but if you play in NG+ you have funds at all camps making fuel and repairing so much easier. Play in survival II so you can unlock the survival trophy as well.
The main things to watch is ammo, fuel, and not riding into water.
If you just stick to yellow story you should be finished in a day or two, even the horde is easy if you have the right guns (i used chicago chopper, MG 55) these guns help big time.
Take your time, and run at your own pace, remember to watch for trap wires between cars as these will break the bike.
good luck everyone :)