The only Montone I see on Google is not close enough to see Perugia/Assisi/Spoleto. I also wouldn't try to catch a flight from there.

Do you want to stay in Montepulciano or outside of town? B&B? Hotel? Apartment?

I would use Bevagna as your base for Umbria--or Spello.

Montepulcinao is a very hilly town and not easy to access by car. I agree with kyb above, name your preference. Frankly, I would stay 3 nites in both of the other Tuscan towns and see Siena as you transition between them.

We found it to be fun to stay inside Montepulciano walls, we drove in to drop off our luggage and then parked our car at the double story parking structure at the bottom of the town. At night we were able to explore and experience the quaint town atmosphere without the tourist crowd as if it hasn't been discovered.
If you book quickly, you may enjoy staying at the Osteria del Borgo which offers accommodation within your budget: http://www.osteriadelborgo.it/default_eng.asp

We enjoyed staying at Meublé IL Riccio in Montepulciano.
http://www.ilriccio.net/eng/index.html

We didn't have a car (just rented one for a day), but they say you can park your car near the hotel:
http://www.ilriccio.net/eng/location.html

We haven't stayed here yet, but are booked in for New Years this year http://www.santantonio.it/

They have a country resort and apartments in montepulciano.

The Osteria del Borgo and the Meuble il Riccio both look great!! and I will check into them for the Montepulciano stay. I would want to stay in either hotels or B&B's--criteria is more the ambience of the place.
I am going to revise my Umbria staying place and am thinking about Perugia. (I will also give some thought to skipping Siena and staying in the other locations longer).
So, any recommendations regarding where to stay in Perugia? Also, should we stay close to Rome the night before we leave for Boston?
Thanks!

jamikins it's WONDERFUL! You will love it. Nico is a fabulous hots, the area is gorgeous and the villas are fab. Oh, and the views!

While Montepulciano is hilly and you probably wouldn't be able to park at your B&B/hotel, there are parking lots and a bus that runs through the center.

http://www.sienamobilita.it/mappe/montepulciano.html

Possibilities in Montepulciano:

http://www.albergoilmarzocco.it/hotel.en.php

http://www.ilborghetto.it/

http://www.politian.com/

http://www.trattoriadicagnano.it/

http://www.ilriccio.net/

http://www.lagnolo.com/la-casa

http://www.camerebellavista.it/

http://www.beblelogge.it/

Right outside Montepulciano:
http://www.albergoilrondo.it/
http://www.villacicolina.it/
http://www.sanbrunorelais.com/

Check locations to make sure, but I tired to list inside the town in the first group.