You shouldn't have to remove the pulley to change the belt. However, to remove the pulley on a MTD, use a pipe wrench to hold the pulley, midway between the two sheaves, and turn the bolt with a socket wrench. You'll leave teeth marks on the body of the pulley but it won't harm FFF. If cosmetics are a problem, you can use a soft strap wrench, like the one Snap-On sells. Cost about $40 but a very nice tool.

To remove the guide pins, they are usually 5/16-18 long shaft bolts, double nutted to the plate that separates the two belts. You can either unscrew each one, or you can remove four small screws holding the plate to the frame and pull the whole plate out.

If you have trouble removing the pulley- pull the engine mounting bolts and slide it back a bit. I had one w/ a twin that I either had to horse it out that way or trash the pulley. It gets the job done.

Try having someone push the clutch pedal in while you remove the belt.
The guide pins just unscrew from the chassis.
Kidd