Gordon Rhea provides a good description in his narrative, The Battle of the Wilderness, May 5-6, 1864, pp. 343-49. He calls the action a "bloody little cavalry fight."

The charge that you mentioned opened the engagement. Gordon Rhea places it near the intersection of the Catherine Furnance and Brock Roads, roughly midway between Todd's Tavern and the Trigg Farm. In the Official Atlas, plate 55-1, you'll see some ore beds in the lower right corner. They may be the nearest landmark other than the intersection.

Custer's Division spent the previous night at Catherine Furnace, about five miles east. His men approached on the same road used by Jackson's men on May 2, 1863. Rosser's column rode SSE on the Brock Road towards Todd's Tavern.