Actually, you need to take the Autostrada past Bolzano all the way to Merano,
where you'll see an exit opportunity for "Dorf Tirol."  That's your exit; a
winding road takes you up to the mountainside village in about 15 minutes,
but watch carefully for the signage, as there are lots of unexpected turn
offs.  There are many lodges in Dorf Tirol, which is a tourist mecca;
availability of rooms depends on the season of your visit. I recommend you
arrange this ahead of time via a travel agent if you'll be there in high
season.  Once in the village, signage guides you to Brunnenburg.  You might
also wish to visit the other castle on the same mountainside, which has an
excellent museum and frequent wonderful music programs.  Pound's grandson is
the director.