Is the official vatican museum 2 hrs in the museum and then you go to sistene chapel? I am concerned if it is too rushed? Is there a time that you must exit the chapel?
If I can get the belvedere tour of underground colosseum should we tour the rest of colosseum before or after and on our own or a tour,
I'll just address the Vatican:
If you're booking what the Vatican Museum calls an Open Tour (not a very good name in English) for a daytime visit, that just means an entrance ticket for your to visit on your own. There's no time limit, other than the closing time or your own plans for the day.
If you book a Guided Tour they say that it takes 2 hours and they probably will leave you at the Sistine Chapel. After that, you're free to continue your visit or exit the museum at your own speed, again subject to closing time.
If you have picked up an audio guide, or used the cloakroom/bag check, or want to visit the gift shop, or really most of the time, you make your way back through the museum to the main entrance/exit. (Sometimes there's an alternate exit near the Sistine Chapel that takes you out closer to St. Peter's Basilica, but it's not a reliable plan.)
Re. the Vatican Museum--Have been to the museum 3x (always just used R.S. book self-guided tour) with the last visit in July 2013. All 3 times we were fortunate enough to exit through the tour group door with no questions asked and we had no audioguides to drop off or stuff at baggage check . If you want to try and take the shortcut from the Sistine Chapel, be sure to take a look at the spiral staircase upon entering the museum as it is beautiful. The spiral staircase is the exit to the museum if after seeing the Sistine Chapel you take the "long march back to the museum's entrance" but you will not see it if taking the shortcut. To see the staircase upon entering the museum: The first thing you do when visiting the museum is to come up an escalator (the 2nd one after scanning your tkt). At the top, if you turn 180 degrees you will see one of the gift shops. In the middle of the gift shop is the spiral staircase. You can go take a peek and pictures but do NOT go down it as you can't come back up. You could also visit the Pinacoteca at this time if planning to take shortcut from the S. C.
Thanks for the advice.
My wife and I are not museum people so we kind of rushed (well, as quickly as one can considering the crowds) through the museum to get to the Sistine chapel where we stayed as long as we wanted. Nobody forced us to leave.