Pros:

-Nice long campaign that is far from a pain to complete in one sitting.
-Pretty easy to navigate.
-Enough supplies placed.
-Plenty of weapons, both guns and melee.
-No problems from the bots. At all.
-Can take your time and explore without fear of constant horde spam (something a lot of custom campaigns tend to do).
-Plenty of wide open spaces.
-Plenty of defibs and frag/incendiary ammo. 

Cons:

-Not many throwables at the finale.
-An arrow directing the players to the boat would be helpful. I found my own way there with no problems, but other players might wait at the radio until the final run.

Conclusion:

You weren't kidding when you said 3 hours of zombie killing action! If anyone else here plans to make a long campaign, this is how you do it. Everything felt it was pieced together just right with a decent amount of supplies scattered throughout. There was never a moment where I felt frustrated or annoyed with anything as I played through. Very well done. A must play for players of any level.