Itinerary help as well!

Is this all planned for one week? I hope not.

You packed as much variety of islands as possible (but still many left out).
Try to group NPs Paklenica, Plitvice and Krka together. NPs are all doable in a day each (if you use Zadar as your base; you can reach Zadar easily from Losinj by catamaran - 2hrs; from there by bus to Pag and NPs). Plitvice and Krka ARE different, however if you have to choose one, go for Plitvice.
Yes, wild camping is illegal. Which does not mean tourists don't do it at the risk of being liable to pay fine. It is up to you.

Thanks for the reassurance :)
Really don't want to miss out on any of the national parks, but it does seem like we have to cut something out to have a more thorough and relaxing trip. The plan is for two weeks actually, and the itinerary still looks too crowded to me... As i'm not sure it would be possible (and especially wise) to do a bike trip through Cres and Mali both in one day for example. And i left out Dugi Otok by mistake, which should be a great dive spot and i wouldn't therefore want to miss. So if you had to cut out an island or two, which would it be? Or any other destination, for that matter (except for the NPs).
Zagreb is actaully not on the itinerary at all, as i'm not really a city-person and don't want to miss out on any activities or nature because of the longish trip. This time at least we are concentrating more on the coast and the islands.
As for the camping, i do not mean to be impolite or incosiderate by any means. It's just that in many countries where wild camping is illegal on paper, it is still widely practiced by both locals and tourists alike. That's why i asked. Also, cause those huge car-park like campings are not really my cup of tea...

Any other help and hints welcome!
M.

Rovinj (maybe some diving?) - nice but very alike every smaller town on the coast
Cres & Mali Lošinj & Susak (biking and hiking and camping and also maybe diving?) - Lošinj has beautiful pine forrests and beaches, susak is a must - skip cres because it's too big (if you don't - visit Lubenice, beautiful small village overlooking at Kvarner bay and if you like try out "janjetina"- lamb's meat)
Pag - party mecca @ Zrće, if you are for it. Rest of it is nice if you want a peaceful vacation but it's also too big for your route.
Paklenica nat. park (hiking) - never been so I'll keep my mouths shut :)
Krka nat. park - very nice, altough a bit hard to reach if you don't have a car. Choose between Krka & Plitvice because they are is quite alike.
Split & Trogir - Trogir is ok for one afternoon visit, you can do Split in transit to dalmatian islands. Visit "Dioklecijanova palača" have a walk around centre and that's it
Hvar (diving?) - Hvar on Hvar gets overpopulated during the summer. If you don't have a yacht, or if you're not a party animal - skip it
Korcula - Nice and sweet - people are very nice. Although if you are short on time - skip.
Mljet - Must!
Dubrovnik - aaah, nice and all that... but overcrowded, overpriced and snobbish a bit. Local people are a fed up with tourists like in Firenze or Venice.
Plitvice nat. park - Either this or Krka. This is croatian most fameous Nat. Park.

Don't know how are you coming to Croatia. If you are landing in Zagreb - go to Plitvice, and than in Pula or Rijeka to catch a boat to Lošinj, and do the Susak too. From Rijeka you can catch a boat to Split (a night ride - sleeping on a deck can be a good way to meet people). From Split you can do a most of destinations in Dalmatia. Go to Mljet and spend a few days in Vis if you can. Dubrovnik - your choice :)
And have fun!

Where are you starting/departing from? Just looking at transportation options usually helps me narrow down a list and cull what doesn't make sense.

I'm sure plenty of people wild camp though it is technically illegal. Though I have to say the campsites I have seen have been pretty nice though (I'm thinking Jelsa on Hvar in particular being really well situated).

I haven't been north of Pag on the coast, so can't help you much there, especially as I only saw Pag town and could have done without it.
As far as the southern islands, I would only skip Hvar because of high season (outside summer it was lovely). Korcula is one of my favorites. I'd choose one or the other. I second the recommendation of Vis, and Lastovo might be a good option as well.

We are coming in from Italy, arriving in Milan by plane, taking a train to Trieste and a bus from there to Rovinj or Pula. And going back the same direction as well. Maybe a ferry to Venice, though it seems quite expensive.
I was also thinking of Vis, particularly cause of the diving options - the blue grotto etc. Also, Pag was on my list cause of the supposed great cave dive options.
I'm thinking of dropping Hvar myself, exactly cause of the high season. And probably Cres in the north as well, as it seems a bit too big, as hungryeyes also suggested.
So that leaves Losnj, Pag (still a maybe, depends on the diving thing, if we can arrange it from Zadar), Vis, Mljet and Korcula from the island part. And i'd still love to do both Krka and Plitvice if at all possible.
Thank you all very very much for suggestions and if you have any further advice (especially on the logistics and transportation) i'd love to hear it!

thanks
M.

Go from Trieste to Pula. There you can catch a boat to Mali Lošinj http://www.splittours.hr/ShipLines.aspx?lang=HR
Lošinj has a diver center too http://www.diver.hr/ too
From Lošinj you can go to Susak http://www.jadrolinija.hr/default.aspx?dpid=1304
and to Zadar http://www.splittours.hr/ShipLines.aspx?lang=HR
Pag is accesible from Zadar - but I would advise rent a car because buses are often crowded.
Than you have to go to Split
(there's a plenty of bus lines from Zadar http://www.liburnija-zadar.hr/kolodvor/raspored_linija.php)
In Split you can catch a boat to Vis - is very beautiful island and very special.
Boat to Vis: http://www.jadrolinija.hr
And in return you can catch that night boat line from Split to Rijeka (I mentioned it before) http://www.jadrolinija.hr
And from Rijeka there's a bus to Trieste http://www.autotrans.hr/

oh, yes, on http://www.jadrolinija.hr/ you can find lines to Mljet and Korcula too.
You can reach Plitvice from Zadar, but it's a bit out of your way so go to Krka instead.

Thank you all very much for your input.
It's coming more and more together now... And no reason to over-plan, guess for a large part we'll just see what it feels like and how much time we have left.
So thanks for all the useful information and ideas and happy travels!