I'd second what Crowe mentioned...PITA, but probably can get a good start with a web search.
Only further suggestion that I'd offer is to call up whichever entity looks suitable and talk through the details of your travel, including access (or lack thereof) to your locations along the way. Obviously, the primary road system in the U.S. and Canada is not a problem. The secondary road systems in U.S./Alaska and Canada are likely not a problem either... but if your travel involves going to locations where you are limited to either bush plane or helicopter access, I'd ask the insurer to identify the specific part of the policy that covers that...and I'd also ask them to walk through all of the exclusions to make sure "remote" is not excluded. One of my clients had a situation where "travel to the nearest airport within 50 miles" and "evacuation from the airport to a suitable facility" were both allegedly covered, but when travel to the "nearest" airport meant either a helicopter flight or a 25-mile riverboat ride (i.e. no roads, etc), the insurer balked.