We are driving around Tuscany in October. Is it useful to download google maps, of places we will be visiting, before we go to Italy? Or, is it just as easy to do while we are at some hotel in Tuscany? We are working with a low storage capacity I-phone, so we don't want to use too much storage (to save for photos), but want to be sure to have the maps when we need them. How widespread is free internet in Italy, generally speaking?
Free WiFi is widespread in Italy.
You can download Google Maps "offline" maps whenever you want, though they expire after about 30 days(?) and Google will make you download them again. The larger the area that you download, the more storage space that will be required on your phone. You can always download just a portion that you will be driving in the next day and download another section that night with WiFi, if need be.
Try it out at home: download maps for your local area, put the phone in airplane mode, and take a short drive somewhere and see how it works.
SIM cards are pretty cheap in Italy, though - maybe 20 to 30 Euros, depending on which plan you get with which SIM (Wind is cheapest; Vodafone and TIM are more expensive, probably better coverage). Your iPhone would need to be unlocked, but you need to make sure it has the right frequencies to work in Europe.
You can download from Google Maps in hotels (but of course book one with free wifi).
I even take screen shots of routes that I've mapped out on Google Maps saved as GIF's or PDF so I can access on a mobile without the internet.
I take screen shots, too, and store them as photos. When I'm done with the map, I delete the photo.
We are currently in Italy and bought local SIM cards (TIM) so we can use data on our phones, especially for figuring out where we are when walking around as well as when driving. For €30 (includes the cost of the SIM card) I got 10GB of data, 1000 minutes of calling and unlimited SMS and for the same amount my husband got a 30 GB data-only plan. We thought it was prudent for at least one of us to have the ability to make a local phone call if necessary. I have used less than 800 MB in a week of prolific use, including driving in Tuscany as well as wandering around using Google Maps dozens of times a day and my husband has used less than 200 MB so a total of 1 GB out of our total amount of 40 GB. While we have encountered lots of so-called free WiFi many times the signal has been extremely weak, so I'm glad we weren't totally reliant on WiFi.
The problem I ran into downloading google maps at our French B&B's was download speed. If you are downloading a map of a fairly large area, it may take a while. I was downloading to an I-pad with limited storage capacity, so understand your problem.
Another thought, if you're trying to save capacity on your phone for photos, create a Google Photos account and set the account to back up all photos from your phone. Then you can delete them from your phone and they will be in the Google cloud but still accessible to you.