I tried the quest, but I kept getting booted during the Haunted Mansion game.
One suggestion for all those who set up quests: I think it's a good idea to put in the quest whether there will be any games and whether a certain score has to be acheived. I mostly do quests with my daughter, who just can't play the games, and some games I'm not as good at either. A few days ago, we tried a quest, working really hard on finding everything together, and then right in the middle of the quest you had to score 150,000 on the fireworks game. We had to quit the quest right then and there, and we were both disappointed that after putting so much work in we couldn't finish. I don't see what the downside is to listing that type of information up front.
For your quest, I am normally able to get 25 ghosts in the Haunted Mansion game, but the computer wasn't cooperating last night. I was surprised to see it though, and did wonder if it turned off others trying to complete the quest. Also, I don't know if you had other games in there with difficult to acheive scores, but if you had, it would have also been a disappointment to come across them with no warning. (Fortunately, that HM game was near the beginning of the quest, so those who don't like playing that game could quit early on.)
Just some food for thought....