@chippyfriday I didn't overplan really, but I had the must sees on my list and they included yours. We were there in September and it was HOT!. I have to confess that I don't do queues, so I was happy enough to see most things on foot from outside, I know some will be horrified that I'm such a philistine, but it would have taken a day or two out of our trip to join the queues for everything. You can book ahead I know, but even with that I didn't bother.
I did queue to see the Papal Audience at the Vatican however, no way around that! It was so memorable and a great experience. Rammed to the rafters though, but was well organised. I didn't go to the museum, far too busy.
There is so much to see and do in Rome that you really can't do it all apart from looking and wandering. Walking is the only way, it is amazing what you come across that way.
I walked from around the Trevi, all the way back to the Colosseum on one day. It was exhausting, but I got to see most things on my list including the Forum, the Pantheon, the Victor Emmanuel, and so on. One church I had to see on my way was St. Ignatius Loyola. It is amazing. Has the most wonderful ceiling and you look at it in a mirror in the nave. I just walked in, and there it was! It's those things that excited me most!
I also took the train from Porta San Paolo to Ostia Antica (30minutes). It is an amazing Roman site similar to Pompeii but without the crowds. If you're into that kind of thing, it is a must do. Down the road from this site is the beach side town of Ostia Lido. I cannot say enough about this place, it was a wonderful break from the frenzy of Rome and so nice to sit having a drink on the beach for an hour or two after trundling around the ancient site. But it all depends on how much time you have and if you could be bothered, since there's so much to see in Rome itself!