I am going to be staying at the JW Marriot in Downtown for 8 days (and over a weekend). Anywhere near there that I could rent a decent road bike and ride? Something on the order of 40-50 miles on Saturday and Sunday. Thanks for any input.

As far as rental, check for bike shops on US 1 ( i dont know of any that rent) , then head over to the key biscayne causeway , two high briges, two low bridges and fellow riders
ocean scenery , head to NO NAME HARBOR ( Real name ) for some lunch

thanks for the information. that sounds good.

How are the drivers in Miami with cyclists?

no comment, since there is no other word i think of to accuratly describe as *&^( terrible

I've gotten to the point that the drivers don't even bother me anymore.

Well almost.

Just gotta keep your head up and prepare for the worst.