I'm late on this one, but congrats on the tag! Those hunts are a ton of fun!
I drew the LE any weapon early tag in the neighboring unit to the north a few years back. I had done a bit of western hunting before but never killed an elk. I began applying 19 years before I drew with the intention of drawing a tag with high enough odds of success on public land that I didn't need to hire a guide.
I live at 650' elevation in PA so I did a lot of walking the summer before the hunt, climbing the steepest hills in my neighborhood, and with a progressively heavier pack as the summer progressed. That and watching my diet to drop 10 pounds was just about all the training I did, but I walk fast enough that I'm a bit winded and my heart rate is up the whole time, but not so fast that I get side stitches and need to take breaks. I just sustain that pace, uphill and down, for 30-40 minutes three or four times a week. That has worked pretty well for getting my lungs in better shape for altitude and for building the core muscles that I use to carry a pack, for several hunts now.
I scouted 2.5 days in July - saw one bull briefly, some cows, but not many elk. I did learn a lot about specific areas and the access I had without using an atv. That knowledge was a huge help in deciding where and how to spend the hunt time.
I prepped to shoot out to 400 yards, but hoped for closer as I don't often have opportunity to shoot past 125-150 at home in PA.
I arrived a couple days early and spent those two days scouting. Watched a wide 350+ six point herd bull twice during those two days, but an archery hunter bumped him and his herd the afternoon before my season opened. The first day I passed on a 5x6 at 80 yards in the timber - partly because he was "just" a five point and I'd kinda set my goal as a 300" 6x6, but also because of that 350 we'd seen the two prior days.
Halfway through the second morning, having seen nothing of the bigger bull since the archer bumped him, I found the 5x6 again and decided I'd be silly to pass him again since he was quite a bit bigger than that 300" goal.
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I may or may not have taken a higher scoring bull had I hired an outfitter but like you, I just hoped for a mature representative bull so this (336 gross and 9.5 years old according the lab) more than met my expectations.
A couple years later a friend drew the muzzleloader tag on the same unit (week after the early any weapon) and I tagged along on his hunt. We saw even more bulls and rutting action on his hunt, so mine was not a fluke.
All that to say that in my limited experience, these hunts are pretty doable DIY given your stated goals. If you need to kill one of the top 5 bulls in the unit, hire a guide for sure. But these units are managed to produce LOTS of the kind of bulls you described.
Regardless of how you go (guided or not), you're in for an awesome time! Best of luck to you!! I'm looking forward to seeing how your hunt goes.