When I moved to SW Montana in the late 70s, there were a dozen or so Unlimited tag Bighorn sheep areas mostly in the wilderness areas north of Yellowstone Nat'l Park. Back then the tags cost $25 and you could buy one every year. The sheep seasons usually opened in early September, and stayed open until the end of November or when the unit quota was filled. There were many years when the quotas of many units wouldn't fill.
The sheep were found mostly in pretty rough country, but in September the high wilderness mountains are beautiful and a great place to be.
I was in pretty good shape then and I backpacked into some of the areas, and other years I packed in with my horses.
It took me several years before I found any rams, but once I did, I killed a ram a year for 4 years. By the late 80s, sheep hunting became more popular, so the cost of the tags went up, and the unit quotas started filling earlier every year, and getting a tag became more and more restricted.
Today, many of those units are either closed to sheep hunting or they were changed to draw units or if they are still open, they must be your first choice in the drawings and the seasons are short and the quotas are low. The high mountains where the rams are found are now also very crowded with both DIY and outfitted hunters. Also, contrary to the BS that the Park Service biologists put out when the released Canadian wolves in Yellowstone, along with the decimated elk and moose herds, the wolves have taken their toll on the bighorn sheep herds.
Looking back, I never knew what a great opportunity I had. I usually only went on one long weekend sheep hunt each year, and if I didn't kill a ram, Oh well, I'd just buy another tag the next year.