But you are right, it will be too many flights and most of the time will be spent travelling just for that 1.5 day in Santorini. Will have to skip it this time. Please advise, if I add these 5 days to spain, what change should I make in my itenary. Does going to portugal make any sense?? Or adding another Spanish city or town would be a better Idea.

I would not add the time to Portugal. Your time in Spain is already incredibly limited. You say, "The Spanish culture and historical sights are what attracts me. The fact that it is different from Central Europe which I have been to before, attracts me." The fact is that each region of Spain is distinct from all the others -- it is a very large country that includes many areas that were, historically, separate kingdoms with different histories and people and cultures. Even if you give all of your time to Spain, you can not possibly see it all and need to make some choices.

I've already given ideas about how I would spend the time you have, but what matters is what YOU want. Here's what I recommend: If you haven't already done so, get some good guidebooks (or spend some time with a few in your local library) and plot your wish list on a calendar. Each time you propose to change locations, pencil in your transportation, add some time on either side (for getting to/from your lodging, checking in/out, packing/unpacking, getting oriented, etc.). Note that each change of location can be "costly" as it is time that you will not have to see or do anything. Then see how things fit together.

BTW, note that many things in Spain are closed on Monday, and often for all or part of Sundays too; and many things in Spain will also be closed daily for a very long mid-day break.

And take janisj's advice about being at your departure city the night before your flight very seriously.

Good luck!

Am i making sense??? Hope so>

Ok that makes sense - but not doing Santorini makes sense too.