I will just repeat some of the info already suggested.
Either rifle should do fine, getting the rest of your equipment might be more advantageous.
I would find a pack board of some kind because if you kill a bull you will take it out in pieces, a good meat hatchet or meat saw. Conditioning should be easy for ex marines, get your mountain legs early on and it will make things so much better for your hunt.
Break in your boots over the summer.
Elk terrain can vary alot but expect lots of downed timbered, underbrush, sliderock.Most drainages / basins have drinking water ( around here)
If you are in your 30's , you are in your prime for these hunts....good luck
