Where can you enter the Roman Forum at? I have read you can buy tickets at Palatine Hill and enter along Via S. Gregorio, but then I also read that this was only an exit.
I also read that you can buy tickets along Via dei Fori Imperiali for the Roman Forum. This is what we would like to do - so we can walk through the Roman Forum to Palatine Hill - exit at Palatine Hill and go up to the Colosseum for our 12:20 tour.
There is no admission charge for the Forum, as far as I know. (The last time I was there was 2008.) Just walk on in! It's open-air ruins, and covers a few acres. The Palatine Hill is at one side (south?). You can enter from Capitoline Hill (near the Wedding Cake monument) and walk through to the other end, near the Arch of Constantine and the Colosseum.
The Roman Forum is now part of the €12 combo ticket with the Palatine Hill and Colosseum. Rick's 2015 Italy book was quite recently updated, and I don't see any further corrections at http://www.ricksteves.com/europe/italy/guidebook-updates, so I don't doubt that you can use the Via S. Gregorio entrance marked on the map on p. 848.
http://archeoroma.beniculturali.it/en/archaeological-site/roman-forum-and-palatine-hill just links to Google maps, so I don't see any better detail there.
