is it a mistake to rent a car to go from Rome to Tuscany to Como in mid October

There is no one rational answer to such a broad question. It depends on what you are trying to do. Tuscany is a large area. Como is city, but you might be referring to the Lake Como, in which case it is a big area - some favor having car, others totally useless.

I guess it really depends. Having a car in Tuscany is a must if you want to visit the small hill towns. Unless you have a city to stop by on your way out of Rome, I would take the train from Rome to a city in Tuscany instead. Don't really fancy the idea of navigating out of Rome.

As for Lake Como, I felt that the ferry rides are good enough. I would imagine that having a car will present its problems in terms of parking and I heard that the roads that run round the lake are single lane, narrow and winding. Don't know how comfortable you are with that. It didn't bother me one bit as I'm from Asia and am use to driving on small roads, etc but what deterred me was the issue of finding carparks at the small towns around Como.

If your interested primarily in cities with train connections, take trains. Schedules here:

http://reiseauskunft.bahn.de/bin/query.exe/en?

For places without connections, traveling through the countryside, rent a car. Routes on viamichelin.

You haven't indicated the length of the trip. On a long trip, you might do both.

No one can answer the question as posed. You need to provide loads more info.

The ferries on Lake Como revert to off-season schedules after approximately the second weekend of October. They still run, but frequency of service is reduced and they don't run as late in the evening. With fewer visitors around, many hotels and restaurants in the smaller towns close for the season.

To give you more helpful responses to your basic question, you would need to tell us the precise itinerary you're contemplating.

Are you flying out of somewhere in northern Italy, or will you return to Rome?

StCirq - Unfortunately, it won't slow the posts.

Can you hear the echo from your post? I certainly can. The OP is absurdly vague.

Rome where? Como where? Tuscany where?

Is it bigger than a breadbox?

Or my favorite, do you bring your lunch or walk to work?