1st trip to Italy Staying 5 nts in Umbria & 2 Rome what cities to visit when staying in Umbria?

Where in Umbria are you staying? Does teh package include anything other than accommodations?

Where in Umbria and will you be renting a car or rely on public transit. You do NOT want a car in Rome but it can be handy in Umbria. Of course, many places can be visited by train/bus so it’s not necessary. But transit connections will need to be a part of your decision - if the bus to city A is nearby and takes 40 minutes vs the one to city B requiring two transfers and 3 hours...your choice is clear!

We are staying in Collepepe and we have a rental car from the Airport in Rome we will be dropping it off when we return to Rome and wont be driving in Rome other than to head to Umbria from the airport.

Where are you flying from? Do you have a van then? or two cars?
I would drop the car off before going back into Rome, whether it is part of the package or not. Be sure all drivers have an IDP and that you are aware of ZTLs. I would check out an Umbria book and go to places within easy reach of Collepepe, such as Todi, Spoleto, Perugia, Orvieto, Norcia.

Flying from Atlanta and yes we have the IDP and each couple has a car.

Not knowing the composition of your group a trip to Florence, 2-3 hrs each way depending on traffic and dealing with Florence's (in)famous ZTL may not be ideal. Siena Is likely to be 1.5-2 hrs one way, so it a bit less driving.

And as already noted, you do NOT want car in Rome

Oh good--sometimes posts can give a false impression, but it sounds like you are prepared. You really only need to read up on the immediate surroundings in Umbria and choose your day trips. I would really make the most of where you will be and save Florence and such for a future trip.

2 nights in Rome equals only 1.5 days for sightseeing at best
Each major site 1 Colosseum 2 Vatican
Needs a good half day and are both exhausting
If you plan to visit both be sure to split them up

I’d choose one so you have time for other things walks, piazzas, minor sites

Also
Driving immediately after an overnite flight usually not a good idea
And trying to keep everyone together in multiple cars will be a real challenge

Assisi which will take a full day. Spello, Montefalco, Bevagna, Datura if you like pottery, Spoleto, Terni for its waterfalls. Gubbio...the list is endless. It's an easy area to navigate. But, use Via Michelin to print out maps to the towns you wish to visit.

I’d also suggest Orvieto and on your drive to Rome consider visiting Villa d’este in Tivoli.

Florence and Siena are in Tuscany, not Umbria.
In Umbria, you have Perugia, Assisi, Gubbio.
I find two nights in Rome is very little, the city is big, should you really want to discover. I would stay at least 3 nights in Rome and the rest for Umbria with a car.
It would be best to get your car in Umbria.

Don't miss Perugia and Spoleto.