Rome Guide recommendations

First, thanks to everyone for the great information, esp. on Tuscany and Umbria. I’ve spent most of the afternoon reading. My husband and I are traveling to Italy this April 9 through April 29 on a “last minute trip,” based on the fact we scored some very good RT tickets from SFO to Rome. Since it’s my husband’s first time in Italy, I want to spend the first 5 days in Rome, then train to Tuscany/Umbria, rent a car and stay for about 7 days, then spend 2 full days in Venice (crowded though it may be because we hit Easter Vacation!) I don’t want to try to push too much in too short of time. We’ll have a few days left to figure out. My questions right now are about Rome. I am thinking that a private guide (or semi private) for one day in Rome would be great, esp. if it includes an early bird trip to the Vatican. Can anyone recommend a good private guide? We will book time at the Borghese Museum (I lived right about the Borghese Gardens in 1971 and I’m sure everything is changed considerably since I was last in Italy in 1989 but I can't wait). We’ll watch the video too. Also can anyone recommend a good food tour, which I’d like to take the first day we’re there to take advantage of what we learn. Finally, I’m thinking about staying in Trastevere, but I’m open to ideas about B&B type lodging or Pensiones. Questions about Tuscany and Umbria may follow. Thank you!