Many thanks for the suggestions. Per the various suggestions, our draft second honeymoon itinerary is as follows. Please advise if there are any glitches you see in this. We'd love to see Sevilla, Cordova, or Granada but seems that the train rides would chew up big portions of our time.
Friday 20th, arrive Valencia
Sat mid-day fly to Madrid (we already have a RT MAD-VLC ticket)
Sun in Madrid
Mon day trip to Avila (or overnight there?)
Tue day trip to Toledo (or overnight there?)
Wed: return to US (our reservation already booked with frequent flier miles)
Thanks again.