Rome on our own for 4 nights & then Gate 1 self guided Tuscany in Montecatini

Here is the suggested itinerary they give from Montecatini. The days are off so not correct

Arrive in Milan and pick up your vehicle at the airport. Drive to Montecatini and enjoy the balance of the day at leisure
Drive Time: 3.5 hours
Distance: 221 miles*
Overnight: Montecatini

DAY 3, Saturday - Drive to Lucca and Pisa
Spend a full day at leisure in Montecatini or drive to Lucca and Pisa. Set off for the ancient medieval town of Lucca, one of the fascinating towns in Tuscany. Walk the narrow streets of the original Roman grid to San Michele and its beautiful piazza, which occupies the site of the ancient Roman Forum. While in Pisa make sure to walk the quaint streets of this Old Maritime Republic and enjoy the medieval arcades of the Borgo Pio, along with views of the city's famous university that has fostered many of Italy's Nobel Prize winners. Also not to be missed is the famous Piazza dei Miracoli, site of the Leaning Tower, Baptistery, and Duomo. Return to Montecatini
Drive Time: 2 hours
Distance: 70 miles*
Overnight: Montecatini
Meals: Breakfast

DAY 4, Sunday - Visit Florence
Spend a full day at leisure in Montecatini or travel to Florence, birthplace of the Renaissance. Visit the Duomo and Baptistery to view Ghiberti's "Gates of Paradise." See the historic open-air art museum of Signoria Square, with its beautiful statues, Palazzo Vecchio, and the Ponte Vecchio "Old Bridge." Return to Montecatini in the evening
*We suggest taking a train from Montecatini to Florence, unless you plan to stay late into the evening. Train service stops around 9:30/10:00 pm.
Drive Time: 2 hours
Distance: 65 miles
Overnight: Montecatini
Meals: Breakfast

DAY 5, Monday - Drive to Chianti and Greve
Spend a full day at leisure in Montecatini or enjoy a relaxing drive to visit the heart of the Tuscan countryside in the Chianti region, where Italy's most famous red wine is produced. View the spectacular setting of green hills, cypress trees, olive groves and endless rows of grape vines and stop for a tasting of the region’s wine & local specialties at one of the many wineries. Greve, once an important market town in the middle ages is considered the entrance gate into the Chianti region and the perfect place to stroll the town and stop at the many artisan and local food shops. Don’t miss to visit the beautiful Montefioralle, a well-preserved small fortified village located on a hill above Greve, and the birthplace of the famous explorer Amerigo Vespucci. Return to Montecatini
Drive Time: 2.5 hours
Distance: 90 miles*
Overnight: Montecatini
Meals: Breakfast

DAY 6, Tuesday - Drive to Siena and San Gimignano
Spend a full day at leisure in Montecatini or drive to visit two of Tuscany's true gems, Siena and the medieval walled town of San Gimignano. Set in the beautiful Tuscan countryside with lush vine escarpments and gray-green olive trees, Siena offers much to see, from fine palaces to the Duomo and Piazza del Campo, where the famous Palio Horserace is run. Then, travel to San Gimignano, a town of Etruscan origin. Built by early noble families, fourteen remaining stone towers line the ramparts of this medieval town, dominating the streets below and creating a beautiful skyline easily seen miles outside of town. Enjoy a leisurely walk through the town's narrow lanes and squares before returning to Montecatini
Drive Time: 4 hours
Distance: 160 miles*
Overnight: Montecatini
Meals: Breakfast

DAY 7, Wednesday - Drive to Parma en route to Milan
Should you choose to drive North to Milan via the A1 Autoroute, why not stop in Parma, home to two Italian delicacies - Prosciutto di Parma and the famous Parmesan cheese "Parmigiano Reggiano". Take a walk through the elegant historic zone and stop to view the baptistery of the Parma Cathedral, considered to be one of the most important medieval monuments of Europe. Weather permitting, cross the River Parma and take a relaxing stroll around the city’s most popular park, the Parco Ducale. Top off your visit with a cheese & ham plate at one of the many local restaurants before you continue to Milan area for your last overnight
** parts of Parma including the historic center have traffic restrictions, but there are pay parking lots nearby. There are also parking lots outside the city, connected to Parma by a shuttle bus
Drive Time: 4 hours
Distance: 240 miles*
Overnight: Milan Malpensa Area
Meals: Breakfast

DAY 8, Thursday - Depart Italy
Drive to Milan airport and return your vehicle prior to your departure flight

So what suggestions when people have on how to do this differently to maximize our experience and time?

I was looking on GoogleMaps, and Montecatini appears to be about 35 miles northwest of Florence--about halfway to the coast. I've never been in the area, but it looks like the mountains are to the north. Should be a good centralized location to do day trips out of.
Too bad the trip's not sooner, but I understand. You're going to be on the edge of winter the first of March, and you can expect average temperatures of 60 degrees days, 40 degrees nights and sunshine 42% of the time. The really great weather in the area is in May--before it gets really hot in summer.
I know you'll have a great time.

Perhaps Gate 1 would let you pick up the car on the way out of Rome (Orvieto?) or in Florence so you don't have to go all the way to Milan. Often there's no fee, or perhaps just a minimal fee, to pick up/return rental cars at different locations within the same country. Definitely worth asking! You got a great price for the airfare alone. Sure, it may be cool and rainy but it could be sunny and warm. You'll be in Italy--enjoy!

Definitely speak to Gate1 customer service. We've used them for our last trip to Rome as well as to Prague and Paris and they can be very accomodating. The most they can say is "no"

You're absolutely correct about asking for different things. The first person I talked to said we couldn't change our itinerary to fly into Rome instead of Milan. Talked to another person and she said it's absolutely fine to do that. So I'm guessing we can work a lot of different things out with them

I'm really curious what others think about the itinerary they gave us to follow from montecatini well we stay there.

It is pretty centrally located between Florence and the coast as someone else pointed out. What are some of the top things you would do in Florence and other places in the area?