I can't really help if you're going to play on pangea. You'll lose most of the benefits of the Norway civ that way, which in large part are built around pillaging from the sea. You can still play as them to get the pillage benefits on land, but it's not going to be as productive.
In terms of war, if you set up your cities in defensible positions (nearby hills for defense, chokepoints that attackers have to come through, lakes/ocean to make siege more difficult, etc.), you should be able to put up walls and get a handful of ranged units to keep off any attackers. Maybe hold back one or two cav units to pop out and take care of any catapults/bombards slowly coming up. On offense, cav ignores ZOC so you should be able to work around opposing units to get at lightly defended cities. It will be more difficult on pangea if you're packed closely together, but still doable.