(NOTE: Be sure to check out the various types of maps available in the drop-down menu, upper right corner. I find the Satellite and USGS Scans to be the most useful.)
I rode the south end of Seaboard Grade starting from just south of Tucker's Grade. This was a nice ride because it was partially shaded by the pines along the grade, but the road was, in a few areas, a bit difficult due to loose sand. This was not a reason to exclude this portion of Seaboard Grade from being chosen as your ride - just be sure that you are aware that you will hit a few loose areas where you will lose traction or maybe even steering momentarily. Seaboard Grade itself ends at about 1.7 or 1.8 miles, but there is a continuing path or trail that will be rideable and interesting in the dry season. It was too wet to ride on a bike the day I was there.