Heavy is nevvy!
Light is might!
I am thinking this way:
2 lightweight struts with roller blade wheels.
The struts hinge down to the ground.
The trick is to make them stay down.
My idea is to introduce a 'stop' when you want them down, and let them harmlessly 'wave' when you are underway. Or, you could also raise them up with lever #2.
Wanna talk?
BoyntonStu