I'm headed back to Madrid for work over Thanksgiving and will have some time to ride towards the end of the month.

I've done a few searches and see National Park Sierra de Guadarrama is close by.

Looking for possible trail guide and bike rental for 1 solid day of riding. I'd bring all my other gear.

I've found the following group:

Mountain Biking Spain – day tours | trackmtb

Any thoughts, tips or recommendations would be greatly appreciated! Thanks.