I've taken a King Air and a Citation over the northern route. St. Johns, Keflavik, Edinburgh, Germany, Italy. Both St. Johns and Edinburgh were a lot of fun. Joel Payne is right about being careful of ATC shortcuts. You can do the northern route across without HF radio. Transition altitudes vary from region to region. "Line up and wait" instead of "position and hold" and other verbage that might be new to you. Routing seems to "as filed" more often that in the states. It should be fun!