Seeing how Franco stayed in power after the war & wasn't disposed until his death in 1975? Would Franco protect them like South American leaders or would they have still been in reach of allied extradition?
I can't for the life of me understand where you have gotten the idea from that Spain wasn't an option for escaped Nazi's.
Spain most certainly was and there were plenty of Nazi's who in one way or another had escaped there. Perhaps the most famous (or rather, infamous) Nazi who spent his post-war years in Spain was Otto Skorzeny, the self-proclaimed 'most dangerous man in Europe' who had built his entire reputation on wartime Nazi propaganda and exaggerations, worked as an arms dealer and a businessman for several different Spanish and West German companies.
Beyond South America, the Middle East was also a very attractive place for former SS and other war criminals to go, but honestly, there are few places where you wouldn't have found former Nazi's. Plenty of them remained in West Germany until they were found in which they moved elsewhere.
As /u/Bernardito points out, there's definitely evidence of former Nazis fleeing to Spain after the war. It certainly wasn't as popular as South America — particularly Juan Perón's Argentina, which was notoriously welcoming to former Nazis. I suspect the reason the Ratlines were mostly followed to South America is a combination of Perón sub rosa explicitly offering asylum to former Nazis and a pretty logical desire among war criminals to put as much geographical distance as possible between them and the scene of their crimes. But some did go there, and lived quite happily for many years — not least because the process of tracking individuals and having them extradited was far more logistically and legally convoluted than it is today.
As an aside: I think there's an implied misapprehension in your question — that Franco was a fascist, or that he had a particularly close relationship with the Nazi regime after the civil war. Nazi Germany and Fascist Italy provided significant support for the nationalists during the civil war, but although Francoist Spain was to some degree aligned with the Axis then and on an ongoing basis after 1939, both Hitler and Mussolini viewed Franco with some personal contempt — and as a conservative Catholic nationalist, Franco was to some degree suspicious of right-wing revolutionary movements like Nazism and Fascism.
That mutual mistrust (or at least, the lack of a true ideological or strategic alliance) crystallised during the Hendaye meeting in October 1940, wherein Hitler notably failed to convince Franco to bring Spain into the war on the Axis side — which is not to say he didn't consider it. Franco was a pragmatic character, and although his regime included some ardent Fascists and had its roots in the Falange, they were largely sidelined once he came to power and began consolidating control and crystallising his sense of what 'Francoist' Spain should look like.
If you're interested, I wrote a longer explanation of Franco's 'non-fascism' in another thread a few months back.
Only now have I even thought of Spain when considering WW2. Funny how I've never really seen Spain mentioned at all until now.