It's fairly easy to License your Snowmobile in Idaho either by writing:
The Idaho Transportation Department
Division of Motor Vehicles
3311 State Street (83707)
P. O. Box 7129
Boise ID 83707-1129
(208) 334-8000
or by going to their
web site in Boise.
Alternative site
Direct link to DMV
For closer to Spokane and Coeur d'Alene, you can write:
Kootenai County Assessor's Office
Department of Motor Vehicles
Kootenai County, Idaho
Tel: (208) 446-1000
Email: kcinfo@kcgov.us
Coeur d'Alene Office
451 Government Way
P. O. Box 9000
Coeur d'Alene ID 83816-9000
(208) 446-1580
Post Falls Office
120 E. Railroad Avenue
Or go to their web site .