All great brands. For lighter duty work with an occasional heavy load well rated backpacking packs are super comfortable and really light in comparison to the heavy haulers mentioned.
In Utah elk units are managed based on average age of harvested bulls. Some units youll be able to draw with those points will be managed for younger bulls than other units. That might be worth considering.
Utah hunting in general suffers from imbalanced supply vs demand. The state does a fine job of distributing permits through general season over the counter tags and limited entry hunts. A major issue is there are just more hunters than elk permits available. Limited entry hunts draw a lot more...
I own bigger magnums and smaller fireballs, but when its time to grab a rifle for the hunt its almost always the 7mm-08 that gets the nod. Ammo was even available on the shelf in Hanksville UT this week during the buffalo hunt.