hi marronn,

I'm not sure that there will be any huge difference in price between Vienna and Budapest on the one hand, and Amsterdam and Brussels on the other, though getting there may be a bit more costly due to the extra distance.

for flights to Vienna [you might fly there, and return from Budapest, or vice versa] have a look at sites like kayak.com. i think that there are direct flights to both from CDG.

one thing to consider if you've not been to Amsterdam before is that April is prime season for bulbs, especially tulips, and in 7-10 days you could do a very nice tour of Holland, including the bulb fields, Keukenhof gardens, etc. we were there at about that time last year and found loads to see and do, staying in Delft and Maastricht. as you sound like active people, there is a lot of the Netherlands which can be seen by bicycle too, using the trains to get nearer to the places you want to visit.

OTOH, Vienna and Budapest are also great places to visit, especially if you like galleries and museums.

Thank you this was very helpful!

I think you are assuming being far as a proxy for being expensive. Is your real concern the total cost of the added portion? If that is the case, you should look at the total cost itself. For example, on April 9th, you can fly Paris to Budapest on Easyjet for 89EU. This portion is more expensive than trains to Brussels or Amsterdam, but you should be comparing the sum of transport+accommodation+food+misc for each option.