I live near Orlando and have been to the Keys several times. We have friends who own a home in Marathon (just about half way to Key West).
The Keys are famous for their water sprorts: Scuba diving, parasailing (on some resorts), swimming, fishing, boating, etc. As far as riding bikes, I'm not sure how popular that is in the area.
What Key are you interesting in visiting?
Most of the people of the Keys are into relaxation, period. Very, very laid back atmosphere.
Key West is probably the most popular destination. It's a little different. For instance, when eating at a few of the outside restaurants, you can expect people to bring their dogs, cats, birds, ferrets, etc to dinner with them. When walking along Duval, sometimes you've got to watch out for the roosters walking along the road. I love taking a trip their at least once a year. Very, very relaxing....but, like I said, different.
Oh, yeah, drinking is a very popular pastime.