We are considering the early morning Vatican tour which meets at 7:00am. We are staying around the Piazza Navona area and normally we would just walk but this trip I have my elderly mother in law and fear that the walk plus all the museum walking will be too much. Are local taxis available at all hours and also does anyone have a guess at the cost for a group of 5?
You can get a cab that will take 5 people, but it is best to call and ask for one. Off-the-cuff, I'd guess 10 Euro from Piazza Navona to Piazza Risorgimento (is that where you are meeting?), but there is a taxi fare estimator online that some people swear by.
Do contact the cab company (I like 3570) and ask for a cab that can take 5 people. If you wander down to a cab stand there may not be any that can take 5 people.
Email your hotel about this. They should be able to give you the correct info.
We did the same tour at the Vatican and had no trouble getting a cab at the Piazza di Tor Sanguigna taxi rank (north end of Piazza Navona). The cost was about €10 for three of us. As you are a party of 5, you might want to arrive at the taxi rank few extra minutes early so a taxi driver can radio in for another driver if needed.
There's also another taxi rank in Piazza di San Pantaleo at the south end of Piazza Navona...
If you have a functional phone, you can also call/text ahead but I believe (but not certain) that the meter starts running when the cab is dispatched. Just look at any cab, or the signs in the taxi ranks, and note the dispatch phone number.
Ask your hotel the night before to schedule a cab for you that can haul all of you. They should be happy to do that. It will pick you up at the front door of your hotel and drop you exactly where you need. Should not cost more than finding a cab at the stand on your own.
One thing you could do for your Mother-in- law is to use one of their free wheelchairs.
I think you must reserve them, but she would not be as tired at the end of the day.