I have found that the Crusader factions tend to be friendly.

There are only two great challenges. The Latin Crusaders, basically three half sized stack of Venetian troops will arrive at Constantinople after not too many turns. Most of their forces are ranged or mounted, or both. Destroying them entirely is an idea as they will hire mercenaries to make good losses. I nearly lost my capital to them, having ignored them after I had almost entirely destroyed their forces. Secondly the Turks have some fairly large forces close to your capital. I attacked almost immediately with what I had in my Anatolian cities, and Constantinople. Those Anatolians possesions of the Turks are not conected to the their middle Eastern possessions, so provided that some forces are kept around Adana (Osman will appear there with a large stack also) and Theodosiopolis few problems will crop up. The province adjoined Theodosiopolis is gold rich (forget the name) and is generally sheltered by some Antiochene possession, so it is well worth taking.

Attacking the Egyptians from the rear while they are occupied with the Kingdom of Jerusalem to take the major objective of Alexandria is usually not that hard. Cairo will probably have Saladin, making it a harder target. I confined myself to taking Alexandria, making peace, and allowing the Egyptians to make life hard for the Kingdom of Jerusalem. Given time the Egyptians tend to be the strongest faction in that portion of the map by far.

I never felt threatened by the Mongols. The Turks usually deal with them effectively, and there are no Timurids, which was a disappointment.