Itinerary from Vienna to Lake Garda

Have you considered flying ‘open-jaw’ or ‘multi-city’ (whatever your airline calls it), into Vienna and out of (maybe) Milan, getting around mostly by train, and only renting a car in one country?

The trains are good. Would you consider doing a day trip from Salzburg to Hallstatt? Check Rome2Rio for ideas.

yes you need to open jaw, fly into one, fly out of another. and don't forget you will be in multiple countries with multiple COVID rules, and you need to make sure you get tested before return to the Big PX following their rules.

would suggest you keep it in one place, either Austria or Italy. there's enough to see in each methinks.

Yes, have been thinking along the lines of multicity flight...into Vienna perhaps, out Venice. The Covid thing may complicate issues so have to be settled on what I'll need between countries to follow rules...still 6 months away so will continue to change and will have to keep an eye on it. Would do just Italy but Vienna has such appeal and have never been there...a shame to leave it out I think. But also yes, partial train, partial trip by train may be something we have to do. My wife doesn't like the pressure of having to meet the train schedule, find the right train, etc...but we can deal with that. And have in the past. Lots to think about. :)

I understand the train schedule issue especially if you are used to infrequent Amtrak services, but most European routes are hourly or at worst every couple of hours on the really long distance ones. If planning for specific trains is problematic you can get tickets maybe the evening before and still find decent prices in many cases.

Although if you know the hotel and when they want check-in, choosing a train will become much easier. Stations are well signed, and English isn't a problem. A number is a number. It is good to know the destination names in the local language. Pretty easy though - Venezia = Venice, Firenze = Florence, Wien = Vienna etc.

I don't know if you will have a smartphone but if you do you can get real time information about the running of your train - in English - and be able to see the names of cities in both English and the local language.

I hope we can help relieve the stress.

your trip is six months away? May as well be in the next century! Everything will change a thousand times by then.

You don’t have to return a car all the way to Vienna, even if you pick it up there. Most car rental companies have.multiple offices within Austria, allowing you to use a second city but avoid second-country drop off fees.
* Villach would be a possible location to drop within Austria and then catch a direct bus or train to Venice, but note that these only run a few times per day on this route.
* You also could dip into Italy with the car before driving to Salzburg and flying home from Munich.

Driving back to Vienna or even Salzburg would be insane indeed, but you could drive back to Innsbruck after lake Garda without too much hassle. A scenic route would be to go via Stelvio pass and enter Austria in Nauders, but that may be ambitious in a day.
Or it is a 3-4 hour drive on the Brenner Autobahn, depending on where you start around lake Garda.