The plan only says the path will lead to Rosalie Island on the MD side. To my knowledge neither the Nat'l Harbor nor the Oxon Hill trail connect to Rosalie Island.

Issues:
1) MD interchanges (for cars) not due to finish until 2011 or 2012
2) Extensive plans for VA side trails, but no concrete plans for MD side trails.

I'll keep my fingers crossed, but for now it looks like you will be able to ride from Alexandria onto the bridge for a view and then head back to VA. Let's hope PG county can get their act together. So far, has it been over 20 years to get the Nat'l Harbor (its latest name) together?

Excerpted from the 9/28/08 Washington Post Dr. Gridlock column: Although the second span of the Wilson Bridge opened to vehicle traffic in May, project managers say much work remains before the pedestrian/bike path across the span opens next spring. The 12-foot wide path alongside the Capital Beltway's inner loop will have great views of the river, Washington, Alexandria and Prince George's County. The pathway will connect the Washington Street deck in Virginia to National Harbor on the Maryland side. Another pedestrian/bikee route is part of the new Wilson bridge. A trail from Route 1 south of the Capital Beltway in Alexandria to the Washington Street deck is scheduled to open this fall. A trail starting on the east side of Telegraph Road at Huntington Avenue and passing over the Beltway to connect with Eisenhower Avenue near Hoffman Center is scheduled to open in late 2009.