Job, I found the following in my notes, but I can't quote the source.
Camp Sumpter was 30 miles from Camp Bragg, 15 miles from Washington, and 60 miles from Camden.
Another entry states Camp Sumpter was between 30 and 45 miles from Camp Bragg.
The following is from the "Fry" Diary: "February 1, 1864, reached Camp Sumpter from Camp Bragg - 4 day march."
Hope this helps!