As others have mentioned, public access is there by the buckets. Bring your other fun guns and maybe your reloading fiddling, they have a good shooting range in town. I dont know about the gas station food, but I actually have had some pizza at Eugenes there, unfortunately that may be the highlight.
Eyes wide open about the off road conditions, the mud can be something else, and be ready for weather surprises, maybe have chains handy? With your crew, you will likely have help if you get in a bind, but you may learn the truth about cell coverages and cell gps optimism.
There is some world class fishing up there too at Peck, but that is big water. You will see some really good Muleys and Pronghorn out on the plains and nice Whitetails in the bottoms, run a decent grill guard if you can. You will probably be within a couple of hours of the upper Missouri River breaks, and go through that area on the way up. It is not always so easy winter traveling if you are planning driving visits back down to CO, or over to MN. Flying would probably be okay, as its easy to get to Denver through Billings. But, good luck if you had hopes of flying with any amount of gear.
I really enjoy the area, and I should try to get back up there now and then, but it is somewhat out of the way. Have fun.
