I believe the cron jobs run in the background, so it shouldn't mess with the Folding, other than maybe stealing some system resources.
Other than possibly poking at the cron jobs with the Terminal or one of the maintenance programs like Cocktail/Macaroni/etc every now and then (a good idea for those of us who close our laptops' lids and put them to sleep when not using them), and possibly repairing permissions once in a while, the only other thing is Software Update.
I've got Software Update set at the longest interval it allows, which is once a week, but only actually update once a month or so. Usually I check
MacInTouch before applying any OS updates or security patches, just to make sure they haven't caused widespread problems.
And that's pretty much it. Except for regular backups....but that's a general computer thing, not a Mac-specific thing.