Be prepared for everything mother nature can throw at you. Altitude can result in wild temp swings = layering. Dry to wet conditions. Rain, freezing rain and snow. Goretex is your friend. Good weatherproof boots, good socks. Light wind proof, waterproof layering is optimal. Merino wool is always good selection along with good outer shell. Gloves are always overlooked but be prepared for cold, wet to dry conditions. Neck gaiters can add warmth without adding another layer. Good solid gortex hat will be worth it when it is rain/snow etc.
Sleeping bags really need to be rated for at least -20 or else you will be sleeping in all your base layers! Foam mat is huge to keep cold out of kidneys etc. Cots are essential to get off the ground. All this is out window if you are spiking.
Wood stoves are nice to warm up for dressing, breakfast and going to bed. otherwise you will be up all night trying to keep it stoked, that's where a -20 rated bag is worth everything. Small fleece blanket inside bag can also be nice addition to keep the heat inside bag. If folically challenged, nice fleece hat for sleeping! Long time ago I started to sleep with a nice fleece hoodie in my bag so I no longer needed a beanie and adds nice warmth to bag.
Last year 2nd season north of Steamboat Springs on WY border we got 3'-4' of snow and we had to bug out of the back country. Always fun taking down a wall tent in horizontal snowstorm! Those dang stakes seem to be driven into roots too! Be prepared with your truck as well; chains, tow straps, come-along, winches, chainsaws, axe, flat tire repair, shovels, sledges and so on. I did have to pull out another truck that was towing a flatbed with UTV on it, Slid off road just a small tad and could not get traction to get back onto it. My truck with chains had enough grip to do so. AAA is not going to help you when no signal! You really need to be self sufficient and try to think of anything that can help you get back out.