I am very familiar with unit 74 as it is only about 30 miles from my homeplace. I have hunted it numerous times, exclusively for elk. In my view the unit can be divided into 3 parts. First is the southern/central part, which is the closest to Durango. Then there is ths northeastern part which is east of Hwy 550 the West Needle Mts in the Weminuche Wilderness area. The northern part is around Silverton and is high country with several 14ers there.
The largest part (southern/central) is divided in half by the Hermosa Creek drainage. It gets the most hunters and the trailheads are used a lot by outfitters. The West Needle has the least access and as a wilderness area, the fewest hunters. The area around Silverton has lots of access as it is old mining country. It is really high country.
Get the San Juan NF map. During the early season, most of the NF camps will be open with campground hosts there. When the hosts leave for the winter, usually by October, they will be closed. September is still our monsoon season so be prepared for rain, thunder and lightning.
If you have specific questions, PM me.