you can easily rent a bike by the day or week in san ignacio. i believe it's the guy at pacz hotel who has a sign out along burns st. there may be other rental locations as well, if you ask around. for a week's rental it comes out the same or cheaper to buy a bike, i think. i did a comparison in summer of 2003.
for tours check with mayawalk or pacz tours, inquire at eva's restaurant or hire freelance local guide patrick warrior at 606.7714. he's mighty mighty and may be able to hook you up with other people interested in seeing similar sights
peace in 2004---