I have been to Rome a bunch of times and have conducted private tours for a school group and adults. Would anyone be interested in me doing a FREE tour of Roma? It would be a highlight tour and I promise to have you on board before the boat leaves and tired enough that you will sleep soundly in the night, curse me in the morning, but be glad that you saved almost $300 a person.
That sounds like a blast. We're thinking of prioritizing the ancient Rome bits over the Vatican bits - as those are the parts of Rome that we'd find most interesting, and that will save the Vatican for the next time... That should (I hope) leave loads of time for some exploring, and getting a bit more in depth, without the pressure of needing to see "everything" all at once... better to really explore a few things than glaze over a lot IMHO