I've made some progress with the second crusader trail and thought i'd share them for any who's having trouble.
The missions are
65-rose between thorns
66- twist in the tale(six progessive save)
Mission 65there is one enemy between you and your ally the abbot-train slingers and archers,immediately,place a low wall and put a few slingers and fire throwers to deal with any attacks from the two Emirs,the swordsmen will retreat after a few losses.when the blue lord is dead you will get some gold use it to buy ale and place an inn,use spearmen to 'remove' farm and industry buildings placed by your ally and place your own.There is some small iron deposits where his quarries are ,again destroy them and place your own.Send some archers to protect your ally as the attacks don't mount to much -reinforce them with other unit types and he should be happy,now you can concentrate on dealing with the two Emirs'.
I used mercenaries with a few european troops.
To attack the right hand emir,send horse archers to clear the walls-mindful of crossfire from the other Emir,instead of going all the way round i used 1 seige tower and deployed it against the straightest piece of his wall-not easy as the arab lords like to build differently to the european ones.
Once the seige tower has docked get your troops on the walls,use archers etc to kill most of the Emirs troops-crossbows and even slingers are devatating at close quarters,use your swordsmen/pikemen to finish this Emir off.
The second Emir-if you have enough troops left you can attack him immediately as he has no gatehouse so go straight in for the kill.If you suffered heavy losses replenish them.
Twist in the tale,this is fairly easy once you have a good economy-place three extra tiles to your stockpile,by stone and wall yourself in,adding two large towers-ues shield from the engineers to protect the archers and fire throwers-these are essential against the merc swordsmen and horse archers -they only attack one part of the wall so it needs constant attention.Dealing with the Emir,there are two ways (1) the oxtether-by-the-gatehouse,only works for so long (2)siege weapons-use trebuchets and spread plague to kill his troops,he has a lot on the keep roof and if you use a seige tower they swarm out and decimate your troops.Fire ballistae are helpful here,if they can target the buildings you should wipeout most of them.You can either buy weapons or produce them ,i bought at first,then made them selling the surplus.When you feel that you have enough troops-swords/pikes/xbows etc use a seige tower but send it round his castle as he doesnt notice it so much,get your archers on the walls then send in the'heavies' for close quarter fighting.This mission was challenging at first as you start with 2000 gold as opposed to the Emir who has 40000 gold,but there is sufficient resources to get enough money,it is a struggle at first.Best food resources are 3 apple farms two hops,place wheat and dairy farms later and sell the bread/cheese(just switch their consumption off in the granary options)
I have added six files for this scenario so you can choose which to play and also take your own route.