I thought that it would mostly be MIA-WPB? From WPB onwards I've been under the impression that service would be pretty close to 110 MPH most of the way.
Also as another thought...stops on the Cascades lines may only be every 30 miles or so, but at the moment on AAF you're looking at a gap of over 150 miles WPB-Orlando (and technically an average distance between stops of 80 miles...though again, the distances are more like 40-40-160 or something like that). Granted, AAF will likely add some stops over time, but not even the most express Acela has that few stops.