Don;
I built the layout with 2x4 framing around the perimeter and then 2x4's down the middle with cross brace 2x4's from side to side and then I have nine 2x4 legs that it sits on. So it is strong enough to get on top of. I am a little guy so crawling around on it is not a problem. I just have to be careful of all the operating accessories.
Thanks;
idea-thinker