There is EMOA, I think their dues are around $75 a year. Just heard of another club in Baker yesterday, but no info on it. I will contact the minerals/mining rep on our RAC and see if she is OK with PM'ing you her contact info, to see if there is anything out there. The outing at Burnt River is like $100 for the three days. The caretakers have put up a post in the chapter events page, with contact info to make reservations.
No chapters over there yet, but Boise not too far away as a last resort.