I recently planned the same trip on a Jeanneau 44from St. Pete to Newport. Your plan is sound. Wesailed from Key West to Jax in 2 days. Hiway 80 (long. 80 W) proved to be a pretty good course with Gulf Stream assisted sog''s to 12+knots. The engine raw water failed in Jax. and the trip was concluded. I bought the ICW Chartpak and never used it. It''s for sale. Do''nt forget a radar reflector and watch your 6.