No idea about buying a pad, but it doesn't cost much to add it to a flight out (£20 as sports equipment - we strapped three together with duct tape and it goes as one item) so it might be worth just taking one or two out with you.
Travel from Valencia takes about 2 hours. Getting out of Valencia is pretty simple (we followed Tomtom's instructions), then you just follow the motorway. There were a couple of speed camera signs, but they tend to tell you exactly where they are.
