Great Allegheny Passage and C&O Towpath, my longest trip to date. 351mi in 4 days. It was awesome. What trails on the east coast are similar in length and elevation that you recommend?

Started in Pittsburgh ended in DC. 80mi day one to Ohiopyle, 90 mi day two to Spring Gap, 80mi day three to Williamsport MD, finishing 100mi on the last day at the mile zero marker.