Thanks for all the help by the
way!
Pleasure!
Thanks for filling in some of the blanks
sarahizzie. Ok, with 20-30 days and more of an idea of the places you want to see and why, this is a skeleton of an itinerary for you to build on:
(not sure where you're flying from,n this may have a bearing on the better-priced city to fly in to)
fly into Madrid Madrid - stay 4-5 nights (3-4 full days - allows for jet lag and some day trips as well as time in the city)
train to Barcelona (fast-train called AVE in Spain, will take 3hrs)
Barcelona - 3-4 nights (2-3 full days - allows for beach time as well as sightseeing and nightlife)
fly to Nice (check Iberia Air as they have cheap and direct flights between Barcelona and Nice, train takes 12 hours and is during the day = monumental waste of precious time in this instance)
Nice - 3 nights (2 full days will allow beach time plus a half-day train visit to Monaco as it's just up the hill from Nice).
train to Paris (the TGV fast train in France will take 5.5hrs or you can fly, but that won't save much time on this route)
Paris - 4-5 nights (I know it's not on your list, but it should be! Unless you've both been here before. You don't have to overdose on museums, there is plenty to see/do/eat/drink without setting foot in one museum if you don't want to).
Lille - not sure why you chose Lille, it's not everyone's ideal European city...but it is good for shopping! You could easily do Lille as a day trip from Paris, or train from Paris and stay overnight before continuing on by train to the Netherlands, specifically Rotterdam then Amsterdam - I know, not on your list either, but stick with me. In fact, let's go with that option...)
train Paris to Lille - the TGV runs this route to Lille in an hour, so you can have an overnight stay in Lille, then catch train to Rotterdam early next afternoon to allow for sightseeing
train to Rotterdam - train will take around 3hrs; again, not on everyone's radar, but still a good town to visit nonetheless. Spend a night here, and you'll have time to explore the city centre and sights, then catch a train to Amsterdam the next afternoon as it's only around 1hr away.
train to Amsterdam - 3 nights (again, lots to see and do, esp Anne Frank House, Van Gogh Museum, the odd bit of nightlife to be had!).
fly to Copenhagen (look at KLM or Norwegian Air for flights - book far enough ahead - min 3 months - and you'll get good prices)
Copenhagen - 3-4 nights (unless there is something specific, 2 full days will give you time to explore the beautiful Tivoli - best seen in Summer and you could easily spend one whole day here - Strøget, the pedestrian street in the city centre, and the harbour area - Christianshaven)
fly homeAs you can see, just that area covers around 25 nights, so not much room for additions, but if you area stretching out to 30 days then you might be able to do more time in some places if you need. I've listed the ideal amount of time (for you) in each city, the idea is that you'll have time to explore and not rush too much, but if you want more time in some cities then by all means adjust. Or if you're thinking of adding one more city in because you have 30 days, then look at somewhere in Belgium (eg Brugge, Brussels, etc) as the train from Lille to Rotterdam will require a change in Antwerp, ie Belgium, so that would be easy enough to throw in.
I've put Spain first and Denmark last as the weather in late June or July will be perfect in Copenhagen, but in Spain and Nice you will still have great beach weather at the start of your trip. If you don't want to add Paris and/or Amsterdam, let me know why. I'm also curious about your choices of Lille and Rotterdam - nothing wrong with them, would just like to have more of an idea as to why you chose them.
The Open Jaw flight ticket is just that - fly into one city and out of another, as shown above. It may cost a little more than say flying in and out of the same city (eg Madrid), so look into it, but it's worth it to save time (and flights). A travel agent may be your best bet for this as you're not familiar with the ticket type.
As for train passes, not sure you're going to get much value out of one for this trip, but again do look into one which covers France and the Netherland (and Spain if it's worth it) and compare to just purchasing tickets in advance on the legs you're looking for. Unless you're heading into a public holiday on the days you travel by train, you can usually purchase tickets for your next leg on the day you arrive in the city. Eg for Nice to Paris, you could purchase that when you arrive in Nice, then travel a few days later. However, look into pre-purchase, esp for the TGV, as this may well save you money.
And remember Copenhagen isn't a "budget" city. It's a little more affordable that it's Scandi cousins further north, but it's still not Spain, so budget more for accommodation and food there.
If you could sift through those details and let us know thoughts/adjustments/additional information that will help with further suggestions and in planning your itinerary. Once you've sorted cities, you can sort accommodation (plenty to choose from in most places, esp hostels and budget hotels) and transport properly.
Some sites which might help you with planning:
Trains:
www.deutschebahn.de and click the English flag at the top right; this is the German train site, but covers all of Europe and is very user friendly. Otherwise go to the train sites for each of the countries you're travelling in, particularly if you speak the language.
Flights:
www.expedia.com www.skyscanner.net or any of the other search engines for flights to see all of your options in one place.