The little micro adventures of a dozen years ago were great one-offs. I have run Jerimond's Orb about eight times, using zombies at least twice, once at 4th of July as a game for the kiddies (disturbingly aware of all manner of zombie movies) till the rain quit. Most are geared for one evening and easy to swap foes without major problems. Just do not use the same map without changing serious features. I also keep a notebook of changes that scale the adventure to various levels and themes. Just by switching 'types' can upset the players that 'read ahead'. I had 2 players actually read a Fey monster while I was setting up the game in with I used that monster as an Undead. Neither has realized my replacement since.