I have used expandable foam in any cracks and the bees still find a way in. Just saying if opening day is warm :shock: .....better safe than sorry. I figure the darker the inside of my box is the less the deer can see inside but they still pick up a quick movement. After using mine for the past years with my young kids I never plan on climbing another tree. The ones I built on running gears are my favorite. If it is muddy I can pull them with an ATV into a field after harvest and pull them out whenever. If you build on rubber wheels they will have more bounce than you would think which can be a shooting issue on a windy day no matter how good you think you have them screwed to the ground. I have let the air out of tires at times and blocked them up at others. Both work. I found that it takes as little as a few days for the deer to start to accept them but with my portable ones I try to set one month prior if I can. By then they don't ever even look at them unless I make noise. I forgot to say go buy a couple cheep cup holders and screw them to the wall for drinks and do a shelf to put stuff on. I'll bet you will find something with you that you wish you had a shelf to put it on. You also need a couple screws to hang coats, hats backpacks and gear from. If done right you never have to move far to reach anything and you dont have a bunch of stuff laying of the floor to trip over or bump into which will make noise. Make sure you over build and way over screw the floor. You don't want a squeaky board. My wife calls my bigest box blind on wheels the "hillbilly high rise" but its way better than a cold tree. It has wall to wall, top to bottom carpet and a nice old office chair in it and I can really nap.. I mean hunt out of it in comfort.