I'm in the process of changing the AC and Alternator belts in the wife's '02 Chevy Tracker, 2.5 V6. What a PITA! I couldn't find much info about the procedure when I searched, but I think I know the drill. Anyway, once the belts are off, what items do I need to pay particular attention to? The car has 105,000 miles, what parts should I look closely at with replacement in mind? I only want to do this job once.

I'd just stay with the owner service manual checklist if you have performed all the routine maintenace to date.  If not, catch up on those requiring attention, draining, cleaning, etc.  If something's not broken yet, don't try to fix it yet.