Sounds like you’ll be better prepared than most guys backpack hunting, if you’re backpack hunting.
With guys in good cardio shape, in steep terrain the number one complaint heard is, “My calves are sore.” Dedicated calf raises are the only thing I’ve seen that takes care of that.
Number two is sore feet from side hilling or going downhill. 95% of that is solved simply wearing properly fitting boots a lot to toughen up feet (not just while hiking) and hiking off trails while conditioning not just following popular trails.
The number three is, “Going down hill with weight sure makes my knees sore,” which is from weak quads that can’t properly support the knee. I’ve had guys who could run a half marathon, but never lift their feet higher than needed walking up stairs complain about sore knees from having to high step over downfall.
Number four is about weak climbing muscles going up hill, even guys with beach muscles.
Our oldest son is great at setting fitness records, but at the end of the day he’s wiped out - a lot of old guy stamina comes from economy of motion, pace, and simply knowing how to walk in the woods, combined with muscle memory.
Each day you’ll know where more time should have been spent - everyone has different natural strengths and weaknesses, not to mention personal preferences while bushwhacking with a pack, and completely different hunting terrain. Just now it reminded me of a dude asking about something similar - turned out they hunt from a truck, only walk about a half mile in flat terrain with great game trails. He could have never moved from the couch all winter, wore Birkenstocks and been fine. lol