Neskowin is a good 40 minutes from Tillamook, and another 20 to the riding areas of the Trask and Wilson River. The Upper Nestucca and Sandlake would be the closest, but still not minutes away. Upper Nestucca is BLM and Sandlake is USFS, for more info.
There are lots of logging roads to explore and you can have some fun connecting the Upper Nestucca and Trask and then Wilson basins if you wanted. Lots of OHV areas near Tillamook...not so much near Neskowin.