Just a couple of points to realise
1 . Finding any guide out here at short term notice is near on impossible and especially one who can speak English and knows the trails.
2. The van hire scenario – Spain is so differant to the UK , if you needed to hire a van at the weekend forget it you might be lucky to find a place open until midday on a Saturday if your very lucky , if you needed to get a hire van in siesta time (2-5) forget it , I dont think Ive ever seen a minibus for hire either , you dont even get 6 seater white cabs here as the local town halls wont issue them a liscense much easier to take two cabs and double the fair.
Your in the height of the season with loads of golfers who have probibly prebooked all the vehicles months ago.