I am not the typical naysayer that this response is about to make me appear, but here goes:
Florida City as a jump off every morning to the Keys/Largo....are you kidding?
The only reason to stay there is if it is a beautiful house, really really cheap, and you plan on diving in the Biscayne National Park area, or scoot down to Carysfort Reef from the Herbert Hoover Municipal marina.
I do that several times a year.
If I am staying two days in the Largo area, I want to be very close to my hotel or rented home/condo.
I want to be on the water, or a 1 minute or less walk to the water wher I can swim, sun, make sand castles on imported sand, or just get lightly inebriated and not worry about driving thereafter.
I pretty much want a 5 minute or less ride from where I sleep to the boat.
A 10 minute ride to a restaurant is OK.
Now....
This is just my two cents.
Do what makes you happy, and good luck!
Chug