Getting there?

You could take a Ryanair flight very inexpensively into Trevisio and BARZI BUS SERVICE can get you to Venice in 40 minutes.

Have you checked Wizz Air? They are the Hungarian airlines I took to the Netherlands from Budapest. My experience was good and I would use them again.

From Budapest to Venice is a whole day on the train. I would love it, others might hate it or find it a waste of time. The trustworthy Man in Seat 61 describes the route on his website (scroll down to get the Budapest to Venice options).

I think David's got it nailed; except it appears that the bus ride is over an hour, then there is waiting for departure time, etc... I would count on 2 hours then be happy if it went faster. Not the greatest paring of destinations. You could also fly into Bologna and spend a night or two in that great city, then take the fast train to Venice....

Hi,

Should you end up opting for the night train, at least, partially, it can be done: Take the Budapest-Munich night train, take the Munich to Venice day train, or, spend the day relaxing, visiting in Munich, then take the Munich to Venice Night Jet train.

Both Budapest and Munich are night train hubs. The advantage of the night train is that both legs are direct.

As Fred says. Once I went to Venice from Brno, had to change trains in Vienna and from there the train was direct all the way to Santa Lucia (Main Train Station in Venice). I arrived around 11 pm and view from the station towards the canal was like fairy tale. Trying to get to Venice from Vienna would be quite shorter than from Munich. When you go from Budapest to Munich you go via Vienna.

Rome2rio.com is my favorite website for finding out transportation possibilities. It shows how to get from anywhere, to anywhere.
It's my bible for going anywhere new!
You can compare prices, time, etc., and see which one works for you.