Played MoM for the second time last night, with a first-time Keeper. We decided to give Scenario 2 a try, having played Scenario 1 last time. About halfway through the game, we noticed that there is a ceremony room on the map, with an alter, that has no apparent entry point, though it has a lock and exploration cards in it. According to the layout map, both doors into the room are barred...so doesn't that mean that there's no way in or out? Seemed odd, and we couldn't for the life of us figure out when or how to get into the room. The Keeper finally just discarded the barred doors, and we went in.

Sounds like you had Ceremony and possible Furnace Room the wrong way. We had that in the last game, only noticed later that they both needed to be flipped and then theirs doors matched. There is a connection to the north (or up) from the Ceremony Room to the Furnace Room if they are both in correct orientation.

We made that mistake in Scenario three... had one of the long/thin rooms with the door facing the wrong way which caused problems until the keeper noticed half way through!