I haven't done Spain but elsewhere there are usually tourist offices. LONG years ago when we took our children and had no reservations we went to the RR station to get a place.

Yes, you can play it by ear, it use to be quite common, finding a place to stay when you arrived in a small town or village, but now, with the advent of the internet, you should at least be able to make a plan, have some idea of where to check when you first arrive in that small village in the middle of nowhere. If you don't, you'll find that you'll end up waisting valuable time trying to locate a place to drop off your luggage before doing any sightseeing, especially during high season. You'll also end up paying more for anything even half-way decent.

It's not something I would recommend, but you appear to be quite comfortable traveling without a plan.

1 Normally go to the tourist office. But you will need to locate them. Not all will be immediately accessible if you wish to drive to the front door, as they could well be located in pedestrianised areas.
2 I really do not understand the fear of loosing your Laptop. At lot of us who live and work in Spain use them all the time.

Note: If you wish to drop your luggage off then usually accommodation establishments have a rule where you cannot enter a room before a certain time. This is to allow the cleaning staff to do their work. So be prepared to either leave your luggage with the front desk or in your car if you turn up very early.

Mid June is not considered high season here in Spain.

I´m not convinced that the locals are a good resource. They know little about the reputation of local hotels because they have no need to stay in them.

Although I live in Andalucía, I use the reviews on www.booking.com as a guide when we planning a trip around Spain. At least you can trust the reviews on there. You have to have stayed at the hotel before being invited to submit a review which is moderated before appearing online.

We often travel without reservations because we do very last minute trips. However, with the internet, every hotel, B&B, etc. has a web site, most with pictures, so we do have sseveral possibilites picked out for each location where we think we might be. As soon as we know for sure where we will be, we call or e-mail ahead. That saves a lot of time when you are actually on the road.

Just about everybody has laptops, but you can probably use a computer at your first hotel to email the others, or stop at an internet cafe. We don't like lugging anything extra around because we travel mostly by train, so now we use our phone or i-pad like device. Lots of different things work.

Tony is right. Unless it is a very small village, it is best to do a big of research ahead.

Tourist offices are your best bet. Most locals have no idea where to sleep.

Thank you all very much. I will reform some of my "non-plans" based on your suggestions. It seems that a bit more travel structure and a laptop are in my future!

If you decide not to reform your "non plans" you may find yourself staying a bit out of the center, which, imo isn't always a bad thing.

Maybe you'd like more commericial hotels and in that case why not make reservations ahead of time. That's the best way to find deals, I think.