Any advice on what to do in Vienna for a few days? What about Budapest?

No clue, but can I go with you?

Are you heading to Austria or Hungary?

Both cities are known beautiful places and
In both places I’d say you’ll find some very interesting museums and historical buildings. Budapest is still a place where you get excellent value on shopping.

I’ll be in both places. two or three days for each.. any advice on where to go shopping?

you should definitely try the local cuisine. i got to eat a green salad with almond oil together with veal schnitzel for lunch. it was truly divine. i can’t exactly remember where the small restaurant was. but it located a few alleys away from the gothic cathedral in vienna. visit the schonberg for a dose of history sprinkled with old world opulence.
walk walk walk. vienna is a wonderful city to explore.