Destinations in Portugal are really close if you get sick of Spain (doubtful that would happen).
After you've explored the bigger cities, head to Andalusia (Southern Spain) for mountains, moorish architecture, and beautiful beaches or to the North East of the country for rolling green hills. Destinations in Portugal are really close if you get sick of Spain (doubtful that would happen). Everything is well connected by plane, train, bus and automobile so it's easy to get around.