Yes you can, but you need to create, and save, the flight plan using the default flight planner. There is no VNAV, so you need to control the climb/descent yourself.

Note. I often create flight plans, with SID and STAR, using FSC, or PFPX, then save them as an FSX, or P3D, flight plan. I load them in the flight sim with the CS 737 selected, and use GPS navigation to follow the route.