My Suggestion is..
What if you created a SAES:RPG Zombie server ? the Zombie will be everywhere around San Andreas and in the ammunation all weapons plus there will be MiniGun/RPG/FlameThrower but with much money like 1 bullet with 100k or 50k and if you killed 1 zombie you will get 100$ or 50$ (low prices because there will be much Zombie in everywhere so you will get much money) and all helicopters/planes will be at the following airports
LS/LV/SF Airports and the hydras/hunters/rhinoos etc will be in Millitary (DE) BC and Naval Bases and if you are interested you can park some in CLO Base or CUBA and there will be carshop and disks to store weapons and park cars etc plus you can repair your car at the repair shop if the zombie damaged your car etc and if interested you can make the zombie with weapons but not with strong weapons like minigun or RPG or flamethrower and the zombie maybe jump on the cars we are driving, if interested you can make a script for dual guns like CLO/DE/CeM and i advice to give it to the players who train with these weapons or the players who kill much zombies like 5k zombie etc and you can get a armor from CLO/DE base or bunkers.
Thanks For Your Time Reading My UseFul Suggestion I Hope You Like It And If You Have Any Suggestions On Zombie Server You Can Suggest It Below In The Comments.