I actually built something like this 3 years ago. I used an old running gear from an old grain wagon for mine. I built my blind 6x8 and can fit 3 guys easy with heater and gear. For windows I used sliding utility windows and I wish now I would have spent more money and got double pane as the single panes fog over very easy with the heater on. However double pane windows are not cheap, especially when you'll need at least 4 with this size of stand. I was able to get a 72in by 24in double pane window from a buddy of mine just for the front window and it will not fog. One thing to not forget is window blinds of some sort to shut or partially shut so you dont sillouete yourself. You will also want to stagger your windows so that when your sitting in the blind a deer cant look in one window and then you be sillouted thru the other side. Learned this very quick since your only a couple feet from ground level this will happen. Carpet on floor is a must. Framed mine all in with 2x4's and the floor with 2x6's. Everything insulated and sheeted with plywood. Then used tar paper to cover sheeting and used tin for the last layer. the two biggest things I would have done different was as i mentioned double pane for all windows, and to do a better job with the door. I just used a sheet of plywood and tried to frame it in, etc but it doesn't seal that well. An actual wood door framed in well would be a lot better. Window base should be at roughly 36in high. Shooting rail/storage shelf using a 1x6 all the way around works nice. For the inside i used drywall to cover up the insulation and painted it all black! This is important!! You want the inside as black as night to help hide yourself. Also get yourself two of those l.e.d. lights that mount to a flat surface and put underneath your shelf so in the morning when dark you can tap those and it will keep the light pointing down but still enough to get situated. small hooks that will screw into wood will also be handy for hanging calls, bags, etc up off the floor. Last but not least.................drill a hole in the corner and mount a funnel with a hose going down into the ground so that when nature calls after about the 4th beer you wont have to open up the door and leak outside
Good luck. If you have questions I'd be happy to answer.