No...the depths are NOT sufficient in the Gulf ICW to carry 6.5....wouldn't do my 6' in places. I would guess 5ft. can be carried on the Florida west cost section...MAYBE 5.5. But you can always come in and go out on planned day hops with no problems. Check you mast height vs. the bridges too as usually 6.5 draft means a tall pole too!
Get a copy of Skipper Bob's guide and use his WEBSITE for shoaling updates etc. that have take place since last revision.
EDIT:PARDON ME...I mis--read the post and thought you were headed to FL west coast! My comments ONLY apply to that coast! Skipper Bob is good for all though!