At the heart of it is a FREE 27"x32" PDF map of a hillfort, customizable with layers that you can switch on and off in Adobe Reader.
Also included is a FREE mini PDF about hillforts, with lots of inspiration for using hillforts in your games along with a handy hillfort name generator.
There are also two FREE 120dpi jpegs of the Hillfort map for Virtual Table Top (VTT) usage.
Check it out: http://drivethrurpg.com/product/249258/Jon-Hodgson-Maps-Sampler--Hillfort. Becoming a Patron is just $2 a month to get a map a month. $3 for all the cool extras.