>>>says a train into Naples takes about 3 hrs<<<

The fast train Rome/Naples takes 1:10, but then you have to get another train (Circumvesuviana) to Pompeii (about 30 minutes). From Florence to Naples would be about 3 hours.

For search purposes, Siena has only one n. You want the rapid bus between Florence and Siena. I don't see the price listed, but I seem to remember paying about 6€ one way.
http://www.sitabus.it/sita-toscana/Firenze-Siena06.pdf

Florence/Pisa by train will be about 6€ one way also.

kybourbon- Thanks for that information and clearing that up for me. Still debating if I should use Naples as a day trip to make it into Pompeii or should i try and stay out that way.

Also, need some help on were to stay to visit Pompeii should i stay in Naples or chose a different location? Would like to see the coast as well.