Really? I speak both french and spanish, so maybe I'm in no position to judge. Maybe you meant just simple signs? I'm pretty sure a newspaper for example would be incomprehensible.
I think he was talking about simple signs, like which bathroom is which. From the spanish websites I've tried to interpret, I definitely couldn't take on a newspaper!
As to the OP's safety concerns, I would suggest that there is a big difference during daylight hours as to after dark especially in larger towns/cities, so make sure you're somewhere you feel safe for the night before the sun goes down. This applies obviously not just to southern europe, but in most parts of the world.
This is a good point, and I keep forgetting that despite the weather being similar to Calgary's summer, the daylight hours are not. Daytime is definitely less scary than night!
The campsites that are closed will most likely be protected by security systems, alarms and/or dogs. Don't trespass! Yes, you would be chased away... at least!
Good to know! Here in Canada I've camped at provincial parks that weren't yet open for the season, and that basically just means that there's a gate down and you can't drive in. Seems like the definition of "campground" is different in Spain though - I'm seeing pictures that look almost like resorts, with pools, buildings, electricity, etc.
Have you considered planning your trip meticulously? Googling for campsites, hostels etc that are open in winter along your route?
I have tried doing this, but from what I can tell most campgrounds are closed in November, and I was having a hard time finding hostels in the lower population rural areas that I'd prefer to bike through. All in all, I'm starting to think that I might be better off just traveling around on foot - getting my bearings with traveling in a foreign country before trying to learn how to bike tour as well.