Originally Posted by Retired in Euskadi

Dealing with your 1st point only, have a good look at a map of Spain. Decide what sort of climate you'd like.
To avoid ex-pats, avoid the Costas. Especially Costa del sol. They have the climatic advantage though.
Anywhere inland will be better for integrating, but it might be rather dead. If you like the sea, there's the Med or the Atlantic.
We have a good climate here in the Basque country, excellent for gardening, though we still get dry periods. And we're close to France. Very few expats.
Galicia is wetter than here. Aragon is lovely; property less expensive than here. Renting first would be better.
Castilla is dry and cold in winter, few expats, and a long way from the coast.
Madrid is a capital like most others and right in the middle.
So, all in all, you're spoilt for choice!