The reason so many Idaho companies are registered out of Post Falls at the same address is there is a company called Registered Agents, Inc. located in Post Falls. Registered Agents, Inc is a national company that helps small business owners deal with small business professional services like registering with with the Secretary of State, legal advice, tax things etc. Nothing shady at all-just small business owners hiring someone to deal with paperwork so they can run their small businesses. Registered Agents does business in most states but to do so, has to have a physical location in those states to offer their registering services.
While I have not used the new shuttle service of out Cottonwood, ID, I grew up there. Did a few reference checks with people I know from my home town who know the shuttle folks. Sounds like good, salt of the earth people and they are not related to the problem company/ies out of Salmon. Grain of salt that I can't comment on their service as I haven't used it but I certainly would give them a try without much worry.