Help with planning a 10-day trip for 4 through Spain- is it feasible??

Hi, I'm a student and I'll be studying abroad in Granada in the Spring of 2007. My family plans on visiting me during Holy Week (March 30-April 9) because I have the week off from classes. Here's what I have planned out so far, but I'm not sure if we should just do a tour-bus deal because my parents are definitely creatures of comfort and I'm not sure how they'll deal with the stress of metros to the hotels and dealing with our baggage... I'd love to show them Spain my way!

I plan to meet them in Barcelona, 2 nights there, Train to Madrid, 2 nights there, train to Granada, 2 nights there, Train to Sevilla w/ only 1 night because we have limited time, train back to Madrid stopping in Cordoba.

Any advice, especially on getting train tickets ahead of time, would be great. I'll be using the Renfe site before I start getting tickets for my family to go to Barcelona during an earlier break, but any advice on reservations, the ticket process, metros, and hotels would be wonderful!

I'd love some tips for QUIET but centrally located hotels/hostals (around 50-75 Euro a night for a double room is what I'd like budget-wise) as well as transportation advice!

Thanks,
Rachel

My only though is that that is a lot of train time - a lot to do in that time period and depending on whether your family wants to see just the bus ride through downtown kind of sights or the quiet strolls through cobblestone street kind of sights... you have to plan your days very carefully - I might chose either Granada of Seville and have an extra day in Madrid and Barcelona ..