If you want a run-down on the rules, check the MTFWP website. If you have specific questions or you're still not clear, the FWP HQ's are out on Spurgin Road there in Missoula.
I was born in Missoula and have hunted the area for 33 consecutive years.
Its went through major changes in that time, and still is going through changes.
IME, (and its extensive experience) if you're planning on hunting within 50 miles of Missoula, I'd concentrate on whitetails. Thats what I did...and still mostly do when I hunt around Missoula. The whitetail hunting in the mountains is not like hunting them in an ag. field...at all. Hunting whitetails in the timber is not easy, but the pay-off of dark antlered, old bucks is well worth the effort.
For some perspective, I've shot a lot of elk while hunting whitetails...
I keep detailed journals, and the BEST week, to hunt whitetails in the area, is from Nov 19-25th, with the peak days being those around the 20-22nd. I've shot some earlier and some later, but 90% of the best bucks I've killed were in that time frame.
I mostly still hunt ridge tops to mid-slope...and I've shot a LOT of big bucks mid-day. In fact, I see more deer activity from 10 a.m.-2 p.m. than any other time (during the days mentioned above). Anyone not hunting daylight to dark during the rut is a fool and obviously arent real serious. Concentrate on pinch points early and late in the day as well as edges.
Once you get into some good areas...I've told my family and friends over and over and over again about still hunting mountain whitetails...its really easy to hunt too fast...and almost impossible to hunt too slow.
As far as mule deer, I'd recommend looking in other parts of the state.
There are some elk around Missoula, but prepared to spend a lot of time figuring that out.
Also note that with the severely decreased lion quotas, whitetails have, and still are, taking an azz kickin' all around Missoula. Not nearly enough lions are being killed thanks to some wrong-headed "trophy" lion bullchit agenda via the houndsmen.
The deer hunting isnt what it was 6-7 years ago, but its still fair.
Good luck.