RE: How do you get in shape.
Ill pile on and also recommend that you wear a pack. I walk alot, sometimes a couple of miles a day and close to a 15 mile hike one weekend a month, and not on flat ground. But, put a treestand on my back, a days worth of food and water on my waist and a gun with ammo and I can't do 1/2 the distance.
My legs were doing all of the work walking around. When hunting I had to carry a lot of the weight with my shoulders and they weren't used to it. So I did two things:
1) Carry some weight when hiking. I do this by doing about 1/2 of my grocery trips (about a mile round trip) with my day pack. When you bring home a gallon of milk, some cans of stuff, etc. on your shoulders two or three times a week, that helps.
2) Move the weight down low. I carry a belt-pack (butt-pouch) with my cleaning gear, water, food, emergency supplies, etc. When I put the stand on my back I park the lower frame on the belt pack so the load is carried on the hips and the arms just have to keep it from falling over. That makes the hill climbing much better and I don't get all stooped over.
Other than that, there is no solution but sweat!