The War 1.5 only has 2 encounters that will definitely need more, the Girplan Slasher and Krek Brimblade. The rest you should be able to do. I did 1.5 the first time at 65 with the help of an 80 druid for all but those two fights. The girplan I did with an 80 Rng and 80 Dru, and Krek was with an 80 dru, an 80 bst, and the 65 War, and it was still a bit challenging as the War had to tank sometimes while the Bst was stunned / knocked back. This was prior to mercs.
EDIT: Second time, I did it all but those two fights molo at 65. Almost wiped on the Girplan this time since the 85 Pal rushed in before others got there, or for me tell him about positioning due to the huge knockback, so the merc was taking a beating and burning up mana fast to keep it's self healed. Luckily other healers were almost there, after which it was pretty easy.
It's been too many years (4 or 5) since I did any of the Monk 1.5 to remember it thoroughly, but most likely, it will have a few raid encounters that will require some help. Seems like 2 fights for the Monk as well that will require more.
Overall, you should be able to do 90% or more without any help. And generally it's not too hard to get help. At least with the War one as the fights are in Bloodfields and RCoD and not hard to get to. It seems like one of the Monk raids was deep inside of Harbringer's Spire, but maybe that was a group fight, I can't remember atm.
Yther Ore.
Edited, Jul 12th 2011 11:36pm by Yther