Mournblade94
Hero
There will be tweaks. I don't believe it is possible to run AD&D RAW... just the initiative system requires house rules. That said...
...no monks or paladins (out of character for a Viking-type campaign)
...no Unearthed Arcana. The basics will be just from the PHB.
...no psionics
...possibly no training
I'll let you know more about the rules as I get closer to running it.
Cheers!
Wait viking campaign with no MONKS!!! out of CHARACTER!!! WHo are the viking s going to raid if there are no monks???

Just kidding really. Monks are the perfect VICTIMS for a viking campaign!