Italy - Advice For Visiting Basilica & Sistine Chapel

Greetings from Rome(!), where my spouse and I have one full day before we depart on Friday. Tomorrow, we would like to visit Vatican City.

My spouse does not have much interest in the VC. I, primarily, want to see the inside of the Sistine Chapel, visit the top of the Basilica, and briefly view the church itself. I'm sure the museum is amazing, but my spouse doesn't have too much interest, and, since it's our last day, we're inclined to do some other things.

Have any advice on how to accomplish this in a single morning?

I've read that one can purchase reservations to the museum/ chapel. And, I've read that one can take the stairs to the cupola, which exitst to the church.

I've thought, perhaps, about purchasing reservations for about 10:00-ish and arrive at the church before 8:30 a.m. to visit the cupola and the Basilica.

Thoughts?

We showed up without reservations and were able to do everything you want to do except the cupola. We would have done that also but had another event (Scavi tour!) to go to. We were able to do this only because we latched onto one of the shady seeming tour guides who prowl the line and offer easy access. Believe me, I was totally skeptical at first of the guy and was really hesitant to follow him to their office and pay for a tour but it turned out okay and there were probably two dozen of us that did the same. You can haggle, probably get two for one for whatever they initially ask. Our guide even equipped us with wireless headsets for the tour before going in the Vatican Museum. Our guide ran us through the museum, pointing out the major exhibits on the way to the Sistine Chapel. After that he left us to wander the rest of the Basilica and VC.