Hey there, welcome to the forum.
I'm afraid I can't help you with riders in Montana personally but I thought I'd give you a heads up on a good way to spot your self some roads to ride in your area:
Go on to google maps, type in your area, and add choose map mode and add the terrain option, have a look around for some high elevations or dramatic changes in the terrain, and of course for cool looking roads! Once you find some interesting looking spots head over to www.mapmyrun.com
and click map new run, and enter in the street name, zip code or what ever you have.
From there you can draw in a "run" along a chosen route (make sure you select "follow roads", it will give you the distance, and total descent/ascent (click show elevation). This is an awesome way to find a good hill to go take a closer look at, find a bunch, add them to your gps and go see what they're like, sometimes you can even go on google street view and check the surface is good. Just took me two minutes to find a road called Brainwood Blvd near Billings that looks pretty sweet and a road off of a street called Hollow Tree road there is a dead end run that looks great! As a general starting point, 40metres descent per KM of distance seems to make for an ok hill. Dead end roads are also a huge bonus, especially if it ends at the bottom of the hill for obvious reasons. Looks like you have some awesome hills to ride around you, can I come stay at yours?
Have fun, be safe.