Use a low energy melee, (tinpot, knife, karambit etc) to be able to walk to ammo stations without taking damage by swinging them every few seconds while walking. A lot of people know this one but some people don't so there
I recomend Molotovs and M202 if you have it
Flamethrower goes through built wood planks but only if you are a high ground angling it down, so build a fence next to the prison map hole, obviously covered up, then mow down those zombies to shreds
What do you think?