Murcia is interesting and doable in a day from Calpe. There you can visit the Cathedral, the Salzillo Museum (Salzillo is the sculptor who made in the 18C. the pieces that are processioned during Easter in Murcia), and the old mill by the river now converted in a museum with the old machinery used in flourmills and exhibits about past, present, and future water technologies. Here you have the Murcia Tourism Website
(with English version).
Albacete? Well, there's a saying in Spain: Albacete, caga y vete (Albacete, sh*t and go!). 'Nuff said.