Vienna Arrival - Taxi from Train Station

How much luggage? Even if everyone has carry-on it takes up a lot of room. Unless there are minibuses, you will probably need two taxis. You might want to look into a driver to pick you up, more likely to get a larger vehicle.

Without knowing exactly where you are staying I'd suggest taking the S-Bahn to Praterstern. It will be the fastest and easiest way to get to Leopoldstadt.

Good question , what is the location in Leopoldstadt ? The U1 goes directly to Praterstern , but its a large area ( I stay in Leopoldstadt on my frequent visits to Vienna. )

Public transport is very good in Vienna.
To find the best route use this: https://anachb.vor.at/
(In the top left there is a menu button where you can switch to English.)
Enter main train station as starting point and the address of your apartment as destination. You will probably get more than one route depending on the time of day. The results will also show the number of changes and the walking distances.

You will definitely need two taxis. But as said above, it makes the most sense to use public transportation. The address of your accommodation would be helpful as the second district is quite big.

Thank you all for replies -- sorry for my delay in response. I think the public transport makes the most sense--reasonable and easy. We are staying on Hafnergasse just a few blocks from Taborstrasse and a few more blocks from Nestroyplatz. Using the trip planner, seems we can take U-1 to Nestoryplatz and walk or U-1/U-2 and get off at Taborstrasse. Correct?

You can do either . but the U2 to Taborstrasse will be a shorter walk

U1 (red line) from main train station to Praterstern, then U2 (purple line) to Taborstraße, followed by a walk of about 250 yards.
OR
U1 (red line) from main train station to Schwedenplatz, then tram #2 to Taborstraße, followed by a walk of about 250 yards.

Thanks Steven and wmt1 !

I think it's 5-8 eu for the train from Vienna airport to the city center via train which is in the basement of the airport. It's very convenient. I have also taken the bus, which was less comfortable. On the train, I usually got to the main train station then take an underground a few stops to Karlsplatz which is walking distance to the inner ring area. In going to Vienna 4-5 times, I have always stayed in the inner ring, and was very happy with my last stay near the opera which is also close to the subway station, markets, the shopping district and Stephensplatz

Thanks RailRider!

The OP's question referred to the route from main train station to 2nd city borough.
RailRider's post referred to the route from Vienna International Airport to the city.

I am not sure whether the OP wanted to know this.

In case that the OP actually will arrive at the airport and wants to go their accommodation in the 2nd borough, some of the previous posts and answers are void, i.e. not describing the best way.

I am not sure whether the OP wanted to know this.

Quite true , but if so , the S7 from the airport stops at Praterstern ,. and then the U2 to Taborstrasse

Thanks all -- good information and more than I needed to know, but always appreciate!