Grant Park Route

About Bouldercrest: Going south on Bouldercrest would take you right to the Intrenchment Creek Trailhead. However, when I biked down Bouldecrest before, it wasn't great after the 5-way intersection with Fayetteville / Brannen / Eastland -- afterwhich (1) it curves and (2) all of it is a No Passing zone. 

To avoid that part of Bouldercrest, you can continue on Flat Shoals and then go south on Gresham Rd.

If you want to avoid going over Ralph David Abernathy Fwy, you could take Brannen Rd from Bouldercrest down to Gresham. The elevation on Brannen is questionable both ways, but it's less cars than Flat Shoals and Gresham. 

The southern-most part between Intrenchment Creek Trailhead and Gresham is the South River PATH Trail. 

There's only one left turn without a stop light or all-way stop: When you're heading back, turning left onto Gresham Rd from Boulderview Dr.