For those of you who play "all-in" games (using every aspect of every expansion) with four Investigators, I offer you the folllowing variant.  Of course, if you play with more or less than four Investigators, your mileage will definitely vary.

Mythos 0 - Turn 4: As you put into play the Mythos card, only place gates in Arkham.  Ignore Double-Doom cards and Rumors.  If you reveal a Gate location on an expansion board, resolve everything else…Monster Movement, Clue token, and Headline/Environment.  Starting on Turn 5, play each Mythos card, as normal, revealing Gates anywhere on any board.  Rationale: In this way, you should, based on the percentages for each Gate opening, have 2-3 Gates open in the first four Turns, instead of 4-5.

Rumors:  Reduce the # of tokens, as if you were playing with two Investigators for Rumors such as Nightmare Pool, but for The Key and the Gate, consider 4 Investigators in play.  Rationale: Rumors should be difficult to pass, but not impossible, given the great distances Investigators must travel when all boards are in play.

Maximum # of Gates: 10.  Rationale: There are 20 Unstable Locations across the four boards.  Ten open Gates represents 50% of all of the locations with the potential to spawn a Gate.

Maximum # of Monsters in Arkham and the Outskirts: 5.  Rationale:  As with Rumors, above, playing as if you had two Investigators would warrant a Maximum # of Monsters in Arkham at 2 + 3= 5 and for simplicity, I've used the same value for the Maximum # of Monsters in the Outskirts.

Expansion Changes

Curse of the Dark Pharaoh: No changes (I currently have incorporated both the original and the new version, so play includes both "Barred from Neighborhood" cards and Patrol Markers. 

Dunwich Horror: No changes

The King in Yellow:  No changes

Kingsport Horror:  Apply a Rift Marker/Token to the Rift Track only when a new Gate opens on any board, including Gate Bursts.  Optional:  As the Rifts occur over the town of Kingsport, Place the newly opened Rift at the location designated by the last placed Rift Marker/Token on the Rift Track instead of at the Gate location on the Mythos card.  Rationale: Performing "Rift Duty" can prove boring for most Investigators.  At least having a potential combat in Kingsport should make things more interesting.  As for the Rifts opening in Kingsport, the very premise of the expansion points out that these tears in the fabric are happening over this coastal city.

Black Goat of the Woods:  No changes

Innsmouth Horror: Place a Deep Ones Token on the Deep Ones Rising (DOR) Track only when a monster enters a vortex.  Additionally, once the DOR Track is full, add a Doom Token to the Doom Track instead of automatically awakening the Great Old One.  This happens during every Mythos Phase while the DOR Track remains filled.   Rationale: Similar to the Rifts in Kingsport, the DOR Track should not be the focus of the Investigator's skills and abilities, but there are times when they may need to travel there and deal with the situation.

Lurker at the Threshold:  You may not use the Power tokens as Clue tokens when the card is exhausted.  Thus, if an Investigator takes a Blood Pact, exhausts the card and sacrifices 3 Stamina to receive the 3 Power tokens, place them on the exhausted Blood Pact card.  During the next Turn's Upkeep Phase, refresh the Blood Pact card, allowing the Investigator to use the Power tokens.  Rationale:  Given the currently accepted rule, it's far too easy to exploit the Lurker.

Miskatonic Horror:  No change

That's it ~ a few tweaks and I can tell you that it works very well.  Again, Arkham Horror isn't about winning, it's a about the story, the theme.  As I've said many times before, "it's about the journey, not the destination."  If I can maintain a win rate consistent with the average based on 10,000 games on Tibs' spreadsheet, while enjoying the game that much more, great!

Cheers, Joe/the Professor