Suggestion:
Viking trading post:
0. Remove the navigation I bonus.
1. tundra tile: +1 hammer and commerce .
2. provides full yield bonus of the tile if city settles on a resource. (this can also apply on many other UB or general buildings.)
3. +1 food from improved fur.
About the navigation I bonus, just give their initial galleys 5 exp each.
Right now, Scandinavia still has too much food, AI Vikings tend to grow large peacefully, build a round highway from Oslo to Denmark and collapse on themselves. This way, we can put more tundra forest tiles there and let it on par or slightly better than plain tiles under Vikings.
By the way, how about change lumbermill from replaceable parts to iron working? Lumbermills are rarely seen in this mod.