What city is a good home base?

Florence-not sure I would want to stay 2 weeks there

Siena is not in Umbria
It is in Tuscany and an easy day trip from Florence

Once you’ve done dome research on other towns you want to visit come back and ask for more specific advice
Your question is unclear and too broad

Agree, need more info.

Consider what your interests and priorities are - everyone has their own.

As luck would have it, I'm currently going through a similar process right now (though for a different part of Italy).

The way I would start the process is to look over all the places you are considering, and make a list of the towns/cities/places that interest you. This can take some time so be prepared to invest some of yours on this task. Use whatever sources you want, a good guidebook is best, plus websites, videos, whatever. If you haven't already, start taking notes and keep all your planning stuff in one place.

Once you have your list, it would be helpful to quickly "prioritize" them, since we all often (usually) have to make choices and trade-offs (because our time is limited but our ravel aspirations are not). Simply go through your list and assign each place a 1, 2 or 3, where 1 = "must have", 2 = "really wanna have", and 3 = "nice to have but optional". Don't obsess over this, it should be a quick exercise. It's entirely subjective, based on your tastes/preference/needs.

Also, with your list of places, take an initial stab at how many days/nights you would hope to spend in each - some could (probably will) be short stops, maybe less than a whole day (day-trips). Others might be a base for 1-n nights. Again, don't obsess, this is just an initial "wild guess" - you will be making adjustments.

So now you have a list of places, which are prioritized for "importance" and also give you some sense of how long you want to stay in each. Now, to start figuring out how it all goes together...

Get a map of Italy that shows the places on your list. Doesn't have to be a pretty/fancy/expensive Michelin map, you can grab something off the internet and print it. Take your printed map and mark a "dot" or circle on each of your places. Use different colors for your 1s, 2s and 3s, or simply use large/medium/small dots for each.

When you're done, you have a good basis for making plans, including:

1. Putting together a rational route.
2. Getting realistic about how much time you have, and how many places you will get to, and how long you will spend in each - the pace of your trip (relaxed and savoring, or a grueling blitz that leaves you crying and exhausted). Just take a stab at it first, you will be revising your plan as you get further into the planning process. That's the hard stuff with hard choices.
3. You now have some skeleton of a trip plan. Time to look further into how you are getting around and fine-tuning your list of "musts haves" versus things you are willing to let go of.

If you're like most of us, you will need to reconcile your wish-list with the realities of how much time you have, efficiencies, and how fast/slow/insane you will be going...that's the hard part. But if you start with the process above, you will be well on your way to creating a good and realistic plan based on your own preferences.

At that point, if things aren't obvious, or if (when) you're stuck on details, come back here and get specific.

Many of us greatly enjoy the planning process (and others hate it). Give it a try and see. Personally, I'm convinced that every hour I spend planning and researching translates into a much, much better trip for me. YMMV.

Hope that helps. Have fun.

How about a week in Siena and a week in Perugia? We've happily spent a week in each, although we didn't go on day trips from Siena, and we had a car for our last 2 nights in Perugia.

If you might want a city that is not in Tuscany or Umbria, there are cities where we've also stayed a week or more that have much superior train connections: Bologna and Padua. From either of those, you can easily get to all kinds of great towns, plus they both have wonderful food markets.

Florence, of course, has excellent train connections, and we have so far spent a total of almost 80 nights in Florence and plan to return, but that city suits our interests (art and language classes) and it may not suit yours. Florence away from the most popular area is very easy to live in --- we like the Sant'Ambrogio neighborhood and the San Frediano neighborhood.