MBPs are not easy to service but it sounds like you are comfortable doing it.
However, right now we don't know if the fan is bad or if its sensor is messed up. The latter might require a new logic board. Apple Hardware Test that came on one of your gray install/restore disks (PLEASE tell me you didn't toss them) will test for a bad sensor or bad fans. Although AHT's results are rather cryptic, a report code with "MOT" in it points to the fan itself. DYI is an option here. If the code contains "SNS" then the sensor is messed up and you likely can't deal with that.
If SNS comes up, consider a "depot repair." You'll need to take the computer to an Apple Store next trip to the mainland and ask for that service by name. They will send the computer to a central refurb facility and basically fix anything inside they find not working properly for a flat fee of about US$315. A new logic board is going to be $700-1100 if they do the repair in-store. The depot repair takes about week, and I'm sure you can arrange for the computer to be shipped to your home address when it's done.
Living in semi-rural Idaho, I understand about getting to a service provider. Until recently, the closest Apple Stores for us were in Portland or Seattle--either is a trip of about 350 miles. Earlier this year, they opened one in downtown Spokane, so that's only 100 miles one-way. Not great but better than before, and no ferries are involved.
