^ Those maps are a little out of date, but are a starting point.
Hmmm... let's see, some good places to start.
For the trail that runs down Crabtree creek you can park and access at:
Lindsay Dr. in Oakpark subdivision, this is the western most (upstream) point of access, nice little gavel parking area.
Further down you could park behind Crabtree Valley Mall under the deck. There is a pedestrian foot bridge that crosses the creek and intersects the greenway. Some people park in the gravel parking lot behind the McDonalds at the corner of Crabtree Blvd. and Blue Rige Rd.
Further down you can park at Lassiter Mill park on Lassiter Mill Rd. The trail is not continuous there so you can't easily go upstream, but if you go north a little ways on Lassiter Mill and cross the road the trail goes for several miles.
Shell Lake park is a great place to access. I usually stay off the loop around the lake because it is so crowded but if you park in the lot below the dam there is a trail that goes under Millbrook Rd. and extends down Ironwood Creek all the way to Crabtree Creek.
Another good place is North Hills Park on Currituck Dr. which has a trail that goes down to the Ironwood trail
These are only a few, but I hope it helps get you started. Maybe you can tell, I really like our Greenways.