Upvote:1
The station home pages and opening times are here http://www.adif.es/es_ES/infraestructuras/estaciones/17000/informacion_000295.shtml and here http://www.adif.es/es_ES/infraestructuras/estaciones/3216/informacion_000382.shtml
It looks like they are both closed overnight (Horario de la estaciΓ³n), so I would expect that you would get kicked out of the waiting room.
AlmerΓa is in Andalucia, so possibly another route rather than via Valencia will be more convenient.
HTH