We don't want to switch hotels but really want to see the green dome. Beside new/old green dome, do we have time to see the other parts of Residenzschloss? We have tickets to Zwinger museums.
It is about 2 1/3 hours each way, with direct train every 2 hours. Seems doable to me if you will not be going that way otherwise.
We did a day trip from Berlin to Dresden, which is only a slightly shorter distance, and found it very doable. We had time to visit two of the three museums in the Zwinger, the green vault, and the cathedral.
Thank you. Are the state apartments and turkish room worth some time?
The bi-hourly long distance train from Prague to Berlin, with a stop in Dresden, is an EC (Eurocity).
Check both Czech Rail (https://www.cd.cz/en) and the Bahn (https://int.bahn.de/en) for prices. For walk-up tickets, Czech Rail, which is heavily subsidized, will have better prices, but the Bahn has advance purchase (Savings Fare) tickets (if you can plan a day trip that far in advance) which could be at a better price. Also check Czech Rail for advance purchase deals.