The Channel Five bridge is probably your best bet.
Here's the list of inlets suitable for most sailboats, beginning in the Miami
area and proceeding towards Key West
These do not have bridges. No inlets for quite some distance and then...
Snake creek - Plantation key - bascule bridge, 7' nominal but presently shoaled to 4.5'. The bascule bridge has 27' clearance when closed. Opening schedule is limited and has changed to become even more limited in the last year or two due to effects on highway traffic.
Channel five - between Matacoumbe key and Long Key -- 7' deep, 65' fixed bridge
Moser Channel - Seven mile bridge - deep - 65'