First one has to understand that the Prince of Kiev only converted to christianity (and easter one at that) in around 960 (not sure). Second, the citys in that region where much more connected to Byzantium and did not know nearly as much about 'western' christians or politics.

Trade routes when north-south and not west-east. For them Constantinople was allready the new super city, most of the old relics where there, the biggest curches where there and the head of the curch was there. So why go to Jerusalem?

At that time, Rus simply was not in the orbite of the western world. If they had anything to do with these wars, then on the side of the Byzantins, supporting them with troupes and things like that.