Welcome to ACA and cycle touring!
It would help if you gave a little more info, i.e. are you going northeast up to St. Augustine following the Florida Connector (FC) and then south on the Atlantic Coast (AC) route to Key West and you want info regarding camping or hotels, traffic, dogs, best beaches for seeing space aliens, etc. Really vague questions tend not to answered.
A few years ago, my wife and I did the Key Largo to Key West portion of the AC, then took ferry to Ft. Myers then northeast on the FC. We went in late March. For us, it was unseasonably cool but luckily, no rain. Depending on when the maps were last printed, I would highly encourage you to double check the addendum for the maps and still verify any required services, i.e. the motel in Metropolis is still open. There were several times when motels or cafés were closed and not on the addendum. This is very unusual for ACA to not have fairly accurate addendum but it was in our case. I still recommend the maps. We enjoyed the trip until I got ill and we had t bail in Wachula, FL.
Prices on the Keys are higher than on the mainland, maybe by 15%-20%. My wife really enjoyed the Hemingway House in Key West (she loves cats). I have done a modified AC route but it was way back in '87 so most info is not relevant anymore.