you are likely not going to be physically fresh when you do kill something, so whatever your packout ends up being, figure on already being worn out when you start. you hunt hard for 3 days, not knowing what to expect, very possibly passing elk up, not knowing the little clues or how to read them, say conservatively you cover 25 boot miles the first 3 days after packing in 4 miles with all of your gear..... not being used to all of this, you are gonna be worn out.... then you kill a bull, and have to pack it and all of your gear back...
if there is some elevation gained and lost (which there will be) packing a bull out solo can be a very tough task even 2.5 miles back, even if you're in shape..... you'll hear tough talk on the internet, but just consider the source, it can be daunting, especially if you are packing your first elk out solo.
I have packed over half of my 15 roosies out solo, and stay in shape and in the hills all year, and it can suck after a bunch of long consecutive days chasing them before you kill one. even a mile in rough country can be tough.
just stay within your realistic means.
i have done a good deal of meat packing between what i have killed and friends, and with time get a little desensitized with how much work is in front of you, but i do remember the days getting back with my first load, smoked, beat up and dealing with the reality there is 3 more heavy loads left.... it can beat you up mentally, and there is only one way to get over that feeling, and that's getting some tough packs behind you.... you don't have that option yet, so don't do anything too crazy, and hunt within your confidence level, it will be way more enjoyable.
use this season to feel things out, still go and do it, just don't ruin it by trying to be super hardcore the first trip.