As alvarezg previously stated;
"Just a comment or a personal view. I am an engineer, and I get paid to make things lighter, smaller, cheaper and still perform. Over engineering is something people say and we all know what they mean, but really it should mean too light, too small, too cheap. "When in doubt, make it stout" is the opposite of engineering. Just my 2 cents' worth."
Well said and my sentiments completely. I like the "lighter, smaller, cheaper and still perform" statement. Thinking out of the box, has allowed me to build a 500 lb, 8 ft woody teardrop, with 1/4 inch sides and top, that has traveled well over 30,000 miles without any problems. My second build has only a 1 3/8" hollow core door for a floor, 1/8" sides and top and tips the scales at a mear 245 lbs. 150 lbs of that is the frame!
Therefore, my NEXT 4 foot long build will have NO frame, only a solid wood floor, 1/8" sides and top, no tongue, no springs, no axle, no fenders, just a single swivel-wheel and a two-point hitch attachment. It'll have a 3 ft slide-out galley to provide a 6ft long bed and if my "engineering" is correct, will weigh in at about 150 lbs.

Roly........here I go again! (I hope)