Rival Heroes
This idea would work best in an undead dungeon because the monsters need to be automated and that fits nicely with mindless dead monsters. I don't know if there are any solo rules on the site but it shouldn't be too hard to come up with them, just move towards the nearest enemy (random if they're the same distance) and attack. The evil wizard player controls rival heroes that start somewhere else and tries to get the gold and stuff before the main heroes. They're not in any way evil so no heroes can attack each other.
Obviously the evil wizard player is going to know where everything is so to make it a bit fairer the heroes could be given a basic map, or just place all the doors and some of the stuff in the rooms so the board itself becomes the map in a sense. You could do things like placing a treasure chest in the centre of a room and when the door is opened it gets moved to the right spot. You could keep track of any money and items the heroes find if you want to bring them back in later quests. This could be used in HQ25.
Obviously the evil wizard player is going to know where everything is so to make it a bit fairer the heroes could be given a basic map, or just place all the doors and some of the stuff in the rooms so the board itself becomes the map in a sense. You could do things like placing a treasure chest in the centre of a room and when the door is opened it gets moved to the right spot. You could keep track of any money and items the heroes find if you want to bring them back in later quests. This could be used in HQ25.