First, welcome to OCC........
With regard to the PTO belt, it is "highly" recommended that you use an OEM Cub Cadet belt (IH-117465-C1) in that it is constructed to handle the bends and twists for this application. As an alternative, one could use an "Agricultural" type of belt, in that the construction is similar. Either belt will be more expensive than the hardware store variety, but in the long run, well worth it. Don't ask how I know this.
Belt alignment is important for optimum use and life. See this link....
Alignment
Get the OEM belt, make the necessary adjustments as seen in the link, and you should be good to go.
Bear in mind, this assumes all the pulleys and bearings are in good working order.