Considering the different places you want to see, I'd do an open jaws flight (into one city, out of another).
Your itinerary is a tough one because Salzburg/Hallstatt are considerably out of the way of your other stops. You might fly into Krakow, head south through Slovakia to Budapest and then to Vienna and on to Salzburg. If you're set on Salzburg, it would probably be easier to fly home from Munich rather than backtrack to Vienna.

I can recommend the Hotel Saski in Krakow. We stayed there in 2003 & enjoyed it very much. It is very centrally located, about 1/2 block from the Main Square. The price included a delicious hot & cold breakfast buffet, with eggs cooked to order. When is your trip?

I would cut one area and try to fly open jaw. Like into Krakow out of Munich or into Krakow out of Slovenia. If you are okay with night trains you can fly into Krakow, see the sites, then night train to Budapest.
I am planning a trip with those cities and plan on doing:
Krakow- 2 days in the city, 1 for Auschwitz, 1/2 day for Salt Mines
Budapest- 4 days
Salzburg- 2 days

lindy27 - how are you planning on traveling between destinations? I've heard from a relative that night train is not a pleasant experience - food and "lodging" not that good; border agents knocking on doors demanding money, etc. How much more expensive is an open jaw ticket than a round-trip one?

althom - Dh is a bit hesitant to drive from Krakow to Budapest through Slovakia - have you done that?

We are taking trains. If you get a double cabin it will be just you and your husband and the door will have a lock. Border agents should not be demanding money but they might knock and ask to see your passport, or they might not (I have never had them do this). We took two nighttrains one from Frankfurt to Milan and Munich to Berlin last time in Europe. I slept best on the Munich to Berlin one because it wasn't through the mountains! We never ate on a night train but ate before or brought our own food on.

People either love or hate night trains. We like to do them to save time but will do maximum 1 a week. I don't sleep as well on them as a hotel but my husband does.

Open jaw prices really depend on where you are flying from, but I haven't noticed too much of a price difference especially since prices to Europe have gone up overall in the last few years. I have noticed from where we live flights to Krakow are expensive but Munich/Vienna are cheaper.

Thank you all for suggestions and questions. Doing more research has led us to forget about this trip for next year. We may eventually get to all of these destinations - but as two or more trips.

lindy27 - how are you planning on traveling between destinations? I've heard from a relative that night train is not a pleasant experience - food and "lodging" not that good; border agents knocking on doors demanding money, etc>

I have four decades of incessant overnight train riding and i can say that what you say about night trains - second hand from a relative is a bunch of bunk - night trains rarely provide any food for one thing - you bring your own - the attendant may sell a few snacks but most such trains have no food service - and the lodging varies as to what you pay - were they in a 6-person couchette or a private double - makes a big difference. Generalities, especially from third parties, should never be made IMO unless you mention a specific night train and specifically why the food was bad - Spanish night trains are one of the few i know that have dining cars though some other countries do but less and less.

For others to get a great fix on overnight trains and their amenities, etc go to www.seat61.com or www.ricksteves.com or www.budgeteuropetravel.com. Now not everyone can sleep on night trains, which always involve some noise - more so in old Eastern Europe with their more rickety-rackety tracks but many folks can sleep well and like to cover ground at night and even save some bucks on hotels, etc.

hi Kelly,

as Krakow and Budapest are your "must sees" why not concentrate on them and the area in between? IMHO both Hallstatt and slovenia really belong to another trip.

if you get open-jaw tickets, starting in Krakow you could work your way down through the Tartar mountains to Bratislava, then take another big loop to Budapest. OR, from Krokow go west into The Czech republic, through western Hungary to Budapet.

When trip planning I think it's always worth looking at a map to give you an idea of what is near where. here's a link to a map that shows just how out of your way both Hallstatt and slovenia are.

http://maps.google.co.uk/maps?rlz=1T4GGIC_enGB310&q=ljubljana&um=1&ie=UTF-8&hq=&hnear=Ljubljana,+Slovenia&gl=uk&ei=BC6ZTLv8KJCQjAfp5I0i&sa=X&oi=geocode_result&ct=image&resnum=1&ved=0CCQQ8gEwAA

"Dh is a bit hesitant to drive from Krakow to Budapest through Slovakia"

Why?

I've been, it's very pleasant driving. Can't deal with an objection that's not defined.