First things first: spring break comes a lot quicker than you expect. And it also requires a lot more organization than you probably think.
Because CIEE doesn't plan anything over spring break, you are able to travel either individually, with family or friends, or with other people in the program if you want. Initially, I was planning on visiting a few countries with three other people in my group here. But, after trying to get them to decide which places to visit, how to get there, and when to go, I quickly decided that wasn't going to work.
CIEE gives you approximately a nine day spring break, but, with travel time, thats really only about seven days. If you are going out of Seville, you need either a plane ride or a train ticket, both of which will take about 2-6 hours on average. Again, it depends on where you are going to visit. Definitely take that into account! When my group tried to plan, they wanted to visit FIVE countries in only those 7 days, which is crazy. I mean, you'd only spend about half a day in each country if you consider that you have to sleep, eat, and travel.
Personally, what I would suggest if you want to travel with a group: plan in advance and make sure at least one person is semi-organized. Probably, the correct order of events would be to plan where you want to visit (limit this to two or three places), buy plane flights or train rides, then reserve hotel rooms. Sometimes, if you go on a site like orbitz.com you can pay for a flight and a hotel at the same time and save a lot of money.
That being said, I decided to go on a tour of Italy, Switzerland, and France with an online tour site that my parents found. I'm going to end up visiting about 12 cities in a seven day trip, and it is all already organized for me. They include most of the travel (minus flying to Paris, where the tour starts) and all of the hotels once the tour starts. Signing up for this was so much easier than trying to plan where to visit myself, and really it costs about the same amount!
Basically, to sum it up, if you want to travel but don't want to have an impossible time of planning, sign up for a tour!