Roma Pass Validity

Yes, you are ok. I did this in Sept. and had no problems. I was even able to do the colosseum, palatine Hill and Forum as a single entry. You just have to look at the map you are given at the entry to the first site and see which entry/exits to use to count this as a single site.
We messed up and went to lunch between the first 2 mentioned above and then into the main gate of the forum. The guard tried to tell us it was not valid, but we persisted that we were told in all places and the Roma Pass info that is was valid......so he let us in. We also used the Roma pass extensively on the Metro and buses - it is a great deal.

Nope. Sorry to disagree. With the Roma Pass only the first two places you go are free. Everything else after that, of the covered places, is at the published discount. You cannot go to a free one, then pay the discounted rate at the next, then have a free one. Your first day is OK, that is one joint site, counts as one entry on your Roma Pass. Then the next two places in Vatican City don't count. The Vatican is a separate country to Italy, and nothing in Vatican City is covered. Castel San'Angelo is back in Rome and is covered. Unless you pay outside the card and don't use the card at all on Tuesday that will be your second entry and will be free. You then will have the discount at the Borghese. OTOH, that will work out to your advantage, money wise. The Colosseo, Foro Romano e Palatino are some of the most expensive tickets - €12, or €7.50 discounted. Castel San'Angelo is also expensive, more than the Borghese. It is €12, or the discounted admission is €8.50. The Borghese is only €9 or the discounted rate is €4.50. You do have to spend €2 per person for the mandatory reservations at the Boghese, no matter if you pay for tickets or they are free. So, although the answer to your question as asked is "NO" you will save money by doing it in that order. My other piece of unsolicited advice is that you may very well be so tired and emotionally drained after your first two stops on Tuesday that you have nothing left for a third. I strongly suggest that you visit the Basilica in the morning and the Vatican Museums in the afternoon. You could probably combine the Borghese and the Castel San'Angelo in one day, just be sure to be well rested before the draining emotional visit to the fabulous Berninis of the Borghese. Also if your Vatican visit is soon it may be caught up in the change of Pope.

No. If you follow this itinerary the Borghese will be at half price and the Castel Sant Angelo will be your second free entry. The pass is set up so that the first two sites are free. There is no way to get around this. Also, the colosseum, forum and palatine hill are considered a combo site and the ticket is good for all three. You have two consecutive days during the validity of the pass to see all three though you can only enter each site one time. The entry fee for the Borghese is 13 euros with the reduced price being 8.50. If there is a special exhibit going on the tickets will usually cost 2 euros more. Either way, I don't think it will matter too much. The reduced price for both the castel Sant angelo and the Borghese gallery are the same. http://www.tosc.it/tickets.html donna

Oh, I see. If thats the case,should i book and pay the reduced price online for the Borghese gallery? Or do i call still for reservations? Thanks for your advice! Appreciate it! :)

Call Borghese for a reservation time. It can be a free site with the Roma Pass. (counts as 1 site)

Just call to make the reservation. Tell them you're using the romapass for the reduced fee. You'll pay when you get there. Donna