I thought that there were more episodes left... or a 'summer season'. I thought I heard something. Oh well

I think that the cop had rented/borrowed the condo at the beach. He said something about making the arrangements.

The problem with a relationship between Beckett and Castle is that the show depends on their sexual tension, close calls, missteps, small jealousies... their chemistry. It is a dangerous thing for a show like that to move a relationship too far any one way. That leads to moments like how the last episode ended. The writers push it as far as they feel they can, and then side-step.