Vacation rental in the Florida Keys ? need tips/advice

Greetings,

Need some information regarding the Florida Keys. We have three families
[6 adults, 4 kids] for a week long trip to the keys. I want to know if
there are possibilities of renting a vacation home for that duration so
we can all be together.

I know these possibilities exist in North Carolina, but I am unfamiliar
with the Florida scene. Need some advice on the following:

1) Are such options available in the Florida Keys [say Key Largo]
2) If so, what advise on what and how to rent a house/beach house ?
3) Which is the more preferable Key [if not Key Largo] for such an
option ? Of course, price, location, beach proximity etc are important
and I am willing to consider any 'Key' location not just Key Largo.
4) For the first week of May, what is the typical price I should expect
to pay ? [I need some references so that I don't overpay.]
5) Lastly, I am open to any other location in FL as long as I can get a
nice rental home for a week, proximous to a beach with warm waters in a
good and secure location.

Any suggestions/tips ?

Thanks.

Juzer