I will be staying at the Hilton Cavilieri in Rome on the GLON 6 night deal then on to Venice.
Two options;
1. take the train through Florence (get out and walk around a bit, eat, reboard then on to Venice. Should take all day and only gets me to Mestre station. I then have to make it to San Marcos from where the Hilton Venice Stucky runs a shuttle. Any advice on getting from Mestre to San Marcos (probably at night)?

2. Fly from Rome to Treviso Airport (on Ryan Air -- two tickets for less than 100 Euro w/ taxes). No via Florence, but only 1 hour flight time. However.... any advice on getting from Treviso (apparently a hole in the wall airport 20 or so miles North or Venice) to San Marco?

Is there a 3d (and maybe better) way?