We plan to travel down the Danube in November. As Hungary does not use Euros would it be advisable to get some local currency
for shopping at Christmas Markets?
At the major markets, they all take credit cards. But never hurts to carry maybe 10.000 in one and 2 thousand forint notes.
This will be a good read as well : https://community.ricksteves.com/travel-forum/hungary/the-christmas-markets-open-soon-in-budapest