There's a squatter in my Sky Condo

Dad and I were putting the trail camera back out, checking the amount of apples on the trees and looking for signs of deer around the sky condo. Dad had cleared away some brush and random limbs and he cut down the tree that prevented me from shooting the deer that he shot last October. We were checking out the area and decided to get a better view - from our sky condo. There are 12 steps from the ground to the floor of the condo. I was 3 from the top when I saw what looked like poop next to me seat. Then there was another pile and another in the corner! Dad climbed up to get a look at the shooting lanes and the reminisce of our squatter. There was some wood chewed from the corner of the wall near where I sit and the roof which surprised us since its treated wood. Dad said its a porcupine (or a raccoon) but either way, it needs to go away before I climb up to my sky condo at 5am in Oct. No surprises please. Any ideas how we can keep the squatters out? Dad wants to put plexi glass up around the condo but Im boycotting. Im not letting him go soft yet - its bad enough I bought him a heater. But, ideally, we will shoot that huge buck that keeps showing up on the camera in October and be done(or have the pressure off us) for the rest of the season.