I have signed up for the tour of Poland in 4/27/27, but I would like to visit Munich or Vienna enroute to Warsaw before the tour begins in Gdansk. I can leave from Seattle as early as 4/21. Have been to both Munich and Vienna when I was in the Army and will visit the other on my return trip. So 1) from which can I easiest get to Warsaw and 2) which should I visit going or coming back to SEATAC?
Lufthansa flies non-stop from Seattle to Munich -- typically 6 days per week in summer and 3 days per week in winter -- April 21 is in the in-between period but hopefully you should have the option of departing at least 3 days out of the week. It looks like Munich to Warsaw is about a 10-hour train ride or a much shorter flight on Lufthansa or LOT; there are also Munich to Gdansk flights (interestingly, the name of the destination on the display board at MUC alternates between Gdansk and its old German name Danzig -- or at least it did 3 years ago).
Vienna does not have a non-stop from Seattle, so it would be "easiest" to visit Munich due to avoiding a connecting flight. Train ride from Vienna to Warsaw is around 8 hours.
Train ride from Vienna to Warsaw is around 8 hours.
Since the tour ends in Krakow, there are several direct trains every day (at least currently) to Vienna taking 5 1/2 hours. Distance is not that far but the train makes 15 stops along the way.
You can get a multi-city (different arrival and departure airports) for the two cities you want to visit before/after.
I agree you should avoid (if possible) a connecting flight on way to your trip so you are not as tired. So as recommended, you could get your first flight to Munich. From there, you can fly or train to Warsaw.
On return, you could could get a train from Krakow to Vienna. And fly home from Vienna, most likely with a connection but I think a connection on way back home is better than the reverse.
You can fly direct from Munich to Gdansk rather than change trains in Warsaw.