Hey Tiny_tazzy!
I do not agree with t_maia that you should only do two countries (I believe that for most of the big cities 3 days is enough to at least get the feel of the city) but indeed 13 cities and still wanting to go off the beaten path is practically impossible in a month. You should take some countries and cities out of your intinerary. It seems that you are especially focused on Pamplona and Budapest because you got specific reasons to go there. In this case I would advice to skip France and go from Barcelona (this city is worth it!) directly to Italy, I have to be honoust and say that I have never been there but according to my brother (he took a month trip with eurail some years ago) Tuscany was one of the most beautiful areas he has seen on his trip.
After Italy go directly to Hungary to visit your family and stay a bit in the east of Europe. Again, I have little experience with Eastern Europe but if you like to go off the beaten path, this is where you should be. Beautiful nature combined with lovely and historic cities and villages. Less touristy and usually cheaper then western Europe.
You should take a look at cheap flights for longer distances and indeed point-to-point trains instead of the eurail pass. Especially in the south of Europe this is usually much cheaper and in case you are really enjoying one country or city you can stay longer because there is no pressure to use up your card.
You will be travelling around in July which means that it can get really hot in the south of Europe. If you are in Barcelona and want to enjoy the sun I would advice you to take a train to Sitges or another coastal town. It is a very short train ride and much quieter and beautiful then the Barcelona beach which will be filled with tourists around this time. The train to Sitges (around 20 min) drives along the coast so you will also get some nice views.
If you want some advice about certain cities let me know
OHannemarie
-snip
Moderator comment: please see Forum Rules
[ Edit: Sorry, no promos please.Link to Forum Rules added. ]