Hi - we (DH, DS7, DD3 and me) are cruising with Holland America next week and will be docking at Civitavecchia on Tuesday 1st November.
We want to take the children round Rome on our own but DH doesn't want to pay for a cruise-organised transfer into Rome and has decided that our best bet is to get the train (even though I've done everything else to do with the holiday, which is a treat from my DPs). So of course it's down to me to look into and organise it... 
Hopefully you lovely MNers can I've me some advice. It's a national holiday on the 1st so that may complicate things but has anyone else gone into Rome on their own and if so, have you got any tips please? The prices seem good so I think we'd get an intercity which is a bit faster as it's still so much cheaper than train fares here but which station would you get off/on in the city?
Can I book train tickets in advance - if so I assume I still have to stamp them at the station at either end before boarding?
Is it easy to get to the train station from the port and back again? Would taxi be best? The DCs are happy to walk but I'm thinking especially on the way back they might be tired so can we just get a taxi outside Civitavecchia station back to the port and does anyone know how much it is?
Lots of questions - answers gratefully received!