Welcome to the forum!
What a great post, Valadelphia! Christine, I'll second every word of it, including the part about not hiring/paying a consultant. The RS forum community is heavily populated with people who organize their own trips, although sometimes with a day or individual-attraction tour here and there. Italy is not a particularly difficult country to travel, and you really only need to rent a car to explore places the trains or other forums of reasonably frequent public transit don't go to. You also don't need drivers for the same reason.
We love the trains. You can often get onto one in the middle of one city/town and get off smack in the middle of another, don't have to worry about skirting ZTLs and pedestrian-only zones, have access to a biffy + ability to get up and have a stretch now again without stopping, and can enjoy Italy's grape without getting behind the wheel (drink-driving laws in The Boot are VERY strict). As mentioned, a rental can be a plus if exploring, say, rural Tuscany but you do not want to leave anything at all of value in an unoccupied vehicle.
At the bottom of this web page is free ebook you can order that will prime you for the ins-and-outs of driving in Italy:
https://italybeyondtheobvious.com
But back to determining where to go/what to do? THAT we can't do for you at the point as only you know what's going to appeal. Golf ? We rarely see questions for that sport in the Italy forums but OK. Bike ride? That's more common than golf, and you can search similar forum threads on the subject. Eat/drink? Can be done anywhere; see previous stuff about driving. Tour? Tour what? Roman ruins? Art museums? Architecture, such as old churches (Italy has FABULOUS churches), palaces, historic civic structures, etc?
You get the idea? That's where guidebooks come in. Go look at some and make notes of what looks interesting. I'm guessing you'll end up with a mix of urban and countryside. I know that the country villa idea is very popular amongst first-timers, and they can work as long as one is OK with the isolation factor, (which doesn't personally appeal to the DH and I) need for a car, and either foregoing wine with dinner or having just a sip or two if having to/wanting to dine elsewhere. On the positive side, biking adventures would be available at many which provide two wheels for their guests. For some of the other Italian treasures - such as art and architecture - you're going to want some time in the more interesting cities. The good news there is that, if planning to return yearly, you don't have to cover ALL of the treasures in any one of those cities all at one time. Just get your feet wet, sort of speak? Shoot, I could spend months in, say, Rome or Florence and not run out of interesting things to see!