Hi TGP,
I just returned to railroading with the Polar Express this year, which led me to decide to add the ARR and a second line for this year. That keeps me in the winter\snow\mountain theme. I am going to use modern freight to start.
I visited the ARR website where you can download some maps of their routes. There are many interesting sections that you could use. The topography and length of the line makes scale out of the question. 500 mile main line and 20,500 Mt. Mckinley!
Amazing valleys, rivers. They service military bases. An awesome bridge. A seaport in Anchorage. They service mining operations. Daily passenger service with stations.
Summer scenes with limited snow. A scenic goldmine, just like Alaska.
I am going to build the FasTrack modules. That leaves me with 45" x 30" areas to build vignettes or scenes.
I found this handy ARR train reference .
Anyway, visit the website for the resources there (maps, pics videos) and that will get you started.
Most of all, Have Fun!