Lake District

Varenna is a good base on Lake Como and Stresa on Lake Maggiore. If you take a train to get between the two towns you’ll need to connect at Milano Centrale (Milan’s central station). Train travel from Varenna to Milan takes 1h 15m and train travel from Milan to Stresa takes 1h.
There is a direct bus between Stresa and Milan Malpensa Airport (MXP) that takes 1h 15m. Instead of renting a car you can get around on the lakes by ferry.

Hello john.zlogar, and welcome to the boards!

A car is generally burden rather than a help in the lake districts. You can only drive the perimeter of the lake and in the case of a really long lake like Lake Como that's a really long way and the top of the lake is Switzerland so it also involves crossing international borders. You get around the lake with ferries - Lake Como's midlake ferry connects Varenna, Bellagio and Menaggio and sometimes go to the smaller towns around the lake as well. You can take a car onto the ferries that support cars but it's a specific process if you've never done it and some rental companies explicitly forbid ferries.

Travel between the lakes is difficult because of the mountains and there's not that much call for it so you'll probably have to connect through a major hub to take the train, but this is still probably only 3-4 hours event to get as far as Varenna.

Varenna is a small, charming hillside community on the eastern shore of Lake Como and depending your tastes people either stay there or in the bigger, fancier Bellagio. Bellagio is easiest to reach via ferry from Varenna and you should visit both for a day trip whichever one you stay in.

You don't say how long you're planning on staying but if it's less than at least a few days in each I'd suggest consolidating down to one longer stay in one place.

Have a great trip!
=Tod

I should have noted that we will spend 5 or 6 nights, splitting it between the two lakes.

I agree with the previous suggestions that the train is the best option in this case. There are a few potentially expensive caveats to be aware of when driving in Italy, and there's no point in renting a car and leaving it parked most of the time.

My usual favourite locations in that area are Varenna (Lake Como) and Stresa (Lake Maggiore).

If you're arriving in Milan, it's an easy trip to Varenna (just over an hour), and that would be a great place to spend the first few days. From there to Stresa is very easy but as another reply mentioned, you'll have to go back through Milano Centrale. There are also a few caveats to be aware of when travelling by train in Italy, so a bit of research on that would also be a good idea.

You might find it helpful to have a look at the current Rick Steves Italy guidebook for suggestions on lodgings in both those places. That would be the best way to pick something that meets your preferences.

We have stayed in Stresa and prefer Bellagio on Lake Como BUT if you plan on taking the train between the two Varenna is convenient. We like Lake Como over Lake Maggiore mostly because we think Lake Como is much prettier. I'm not sure I would pick these two lakes on the same trip I might suggest one of these two than Lake Garda for something different.