weberlin, hopefully you can rent your condo for a positive cash flow (or break even). If you put it on the market and it hasn’t sold by the time you have to move, you may have to rent it out and rent in at your destination.
I’ve been there a few times and my favorite areas are Gaithersburg, Chevy Chase (MD) and McLean, Great Falls, (N. VA).
Most of Fairfax County (VA) is exceptionally beautiful and tranquil (read: downzoned), especially right along the Potomac. IMHO, it is a vastly different world than SD County.
I don’t think Great Falls has any condos at all and Chevy Chase has some (older refurbished). The other two areas have many.
Piggs investor and eavesdropper have lived in N. VA many years and can give you better advice.