Yep - at least part of it is accessible on NPS land.
I re-traced Wofford's brigade for @lellott19 back in January 2022. The flank attack assembly point initiated at the unfinished RR bend.
Here's a picture I took of the old RR bed. If you follow the snow line, you will see the bend in the RR bed turning north, just as period maps indicate as the assembly point.
View attachment 474961
Also the elevation is a little higher there than at the Union line - equaling easier marching/charging for the Southerners. If you walk straight from the RR bed towards the Union line, you'll soon come to the Ni River (stream) just as period maps show. The Ni "river" was the point where Wofford struck the Union.
View attachment 474960
If you PM me when you are ready, I will be more than delighted to take you there.
I recommend late fall - winter for several reasons (1) you can see the unfinished RR bed better (2) it's a good hike if you want to follow Longstreet's path (3) there are plenty of copperheads in that area in the summer
(4) chiggers & mosquito are plentiful.
With that said, if you still want to go in the summer, my offer is still good - just have some good snake boots.
The big development that borders the unfinished RR is Fawn Lake, developed by Joe Gibbs (Washington Redskins and NASCAR fame ) and a Mr Meadows. During the war, all of the development was a part of the Greenfield plantation, ancestral home of my friend Pat Sullivan ( Spotsylvania Memory blog).