Neat. I'm venturing a guess the routes to Bowie and Laurel would follow the MARC tracks... and thus, Muirkirk, Bowie, and Laurel stations would be located at the MARC stations.
Though it’s not in the text description the MARC stations at Collage Park and Muirkirk would be closed.
Burtonsville, Scaggsville... never thought of... or Crofton.
Bowie, Crofton, Pointer Ridge, Upper Marlboro, Pinefield and Waldorf are at the Norfork Southern Popes Creek Branch this would become a MARC line from La Plata to Baltimore.
Centreville... thought of it as an Orange extension, with Chantilly as a spur route.
VA US-29 Lee Highway run parallel to VA I-66 about two miles to the south that why a ran the K Route Orange line out VA US-50 Lee Jackson Memorial Highway to Chantilly this would give better coverage along VA US-50 and areas south of Reston.
Waldorf, yes... your eastbound Green/Blue extensions surprised me.
And regarding southbound Blue and Yellow... great minds think alike, eh? Only I'd had the Yellow going west from Fort Belvoir, flyover junction (a la Rosslyn, L'Enfant Plaza, D&G junction (is that within Stad-Arm's territory?)) north of Lorton, and end Yellow at Woodbridge (with the Blue trains alternating between terminating in Lorton, Fran-Spring, or Woodbridge depending on time of day)... this was a more recent idea, and involved a pocket track south of Lorton as well as Woodbridge.
One of the Reason my Pink Yellow lines go no farther south then Fort Belvoir is it would be redundant to run so close to the Blue line south of Newington.
I wonder if Metro ever considered this... Newington is a growing area, and traffic ties up quite a bit during rush hours between Woodbridge (and Dale City) and DC... having both trains go there would ease highway congestion, AND prevent overcrowded Blues.
Acutely my fantasy is a blown up version based on a WMATA Transit Service Expansion Plan that was published in 04 1999
John