If your wheel is 6 inches in radius, then the required torque is 6*12 = 72 inch-pounds minimum (in the antiquated system of units used only in the U.S.).
Thanks for the reply! The torque number matches what I thought it would be. I believe I need to find a small electric gear motor that will move at 2 RPM and that torque. It seems hard to find from my preliminary searches. Would you have any experience or advice in this area?