The best hunting in 6a is in the San Pedro Parks wilderness area which is accessible by foot or horseback. Pretty close to what you'd get on the Valles Caldera. There are still lots of good areas that are accessible from a roadside camp. But like lots of public land you're gonna have to walk a mile to get away from the crowds. During archery season you will get a lot of other users of the forest as well. Its all ponderosa pine, fir and apspen with some scrub oak as well.
6c is kind of divided into a northern section which is accessible from State road 96, Youngsville, or the southern section accessible from State road 4. The southern section has taken the brunt of the fire activity but those burn areas are extremely thick and providing some great feed. I have seen some very heavy horned bulls coming out of the Jemez in the last few years.
All of the Jemez has a lot of roads and can be hard to get away from people. 6c is easier to draw, has more pressure, and holds a good number of elk. 6a is harder to draw, has slightly less pressure and, less road access but if you don't go into the parks its not much different than 6c. Of course both border the Valles Caldera and hugging the border is always an option. 6c can also get tricky with borders with Bandelier National Monument, DOE, and Valles Caldera so a GPS chip is a plus.
I haven't hunted/guided in 6a/6c for 6 years but have a buddy that's killed 3 bulls in the last 4 years in 6a/6c all over 300. He won't tell me where he's going though! He's also in his late 20's and spends every weekend in the woods. I would pick a unit and if you're willing to make a long term commitment to it in a couple of seasons you'll have your own honey holes nailed down.
If you want the name of a reputable outfitter pm me, especially if you draw the Valles Caldera. Its worth having someone with experience out there because it can be overwhelming with the shear # of elk. If you have specific questions after you've done some research pm me and I'll try and help you best I can.