Hello Jeanne. I am a bit too far away from the US to comment on dealers. I am sure if you run into a problem on the road a quick post to this forum will elicit both a reference to a nearby dealer and perhaps even a visit from a fellow MOC'r. Even if you don't have any problems, letting people know what campground you are in might result in an opportunity to meet someone with local knowledge and some good stories.
With respect to tow vehicle, a quick search of the forum will turn-up a lot of conversation, debate and even a wee difference of opinion, sometimes emphatically stated. It all comes down to your comfort level. Any diesel engined truck made by Ford, GM (Chevrolet or GMC) or Dodge in the last 8 years will have the towing capacity for either of the Montana models you are considering. The problem is they may not have the rated capacity to carry the weight of the trailer that the truck takes from the connection to the trailer. This is called the pin weight and is transfered through the connection pin, to the hitch in the bed of the truck to the truck frame and suspension components and finally to the truck's wheels. This rated capacity is set by the truck manufacturer. I have given some links below that will help you understand the concepts, jargon and help you make an informed choice for a tow vehicle. It all depends on whether you wish to stay within the capacities set by the truck maker or not.
http://www.trailerlife.com/ This is a good place to start. Just choose the 2007 year in the towing guide section on the left column.
http://gm.ca/gm/english/shopping/pic...ck-guide/start This is guide from GM Canada for selecting a pick-up truck from their line-up. It is a bit complicated.
http://www-5.dodge.com/vehsuite/TowingGuide.jsp Dodge's site for towing and payload capacity.
https://www.fleet.ford.com/showroom/...ng/default.asp Ford's towing guide.
If you ever decide to make a trip to Newfoundland let me know and I'll assist in any way I can. If you have any questions, you can post them here or PM me using the forum's message system. Just double click on my user name.