Here is what I am doing for a cart. I used some scaffold wheels and had some heavy wall pipe and came up with this design. You definitely want to have brakes on the wheels. I will install some pipe clamps to secure the frame to the cart which will make it easy to roll outside too. I ran a 2x6 and 2x8 on the frame, making it easy to shim the body if needed when metal install starts. This moves around real easy and is extremely solid. Still have the ability to use jack stands on the rails when needed.