OK thanks Pete. It seems like a strong, simple & inexpensive plan to me. I really appreciate any & all experienced opinions. I don't want to make a really silly design decision at this stage! I finished my po' man's mag drill so today I start drilling & tapping some holes in that beautiful top!

Roger, you may be right that I don't need the "wheelie bars." My plan is to wait until it gets the heavy stuff on top & I'll shove it around & see what it feels like. If it's top heavy & unstable, "wheelie bars" it gets. It has to be moved around quite a bit for access to the stuff stored behind it.