I rode it yesterday West to East, and today East to West, as I made my way on the 10 mile journey from Georgetown to Don Beyer Volvo in Falls Church.
As others say, especially East to West, the hills are a bear because you're climbing up from Rosslyn, I guess more or less in the direction of Great Falls. Anyway, you're going up river, and the elevation increases.
Anyway, I'm grouchy about it not because the Custis goes uphill going West, which is natural, BUT I RESENT that it must needs play leap-frog with Rt. 66, as the trail either goes above exits on flyovers, or below certain exits, or indeed even having to climb up a steep curlicue ramp to reach the pedestrian bridge that crosses from the North to the South side of Rt. 66 (going West, that is). Eventually the Custis ends at the W & OD Trail, which is a great success of course, and goes all the way out to Purcellville, Va.
But when I need to go West out to Falls Church again, I will try to find the Eastern terminus of the Bluemont Junction Trail, which then connects up with the Washington & Old Dominion Railroad Trail, in other words, a route that follows a more RATIONAL, flatter, train route. Harumph to cars, and the bike trails that must bow to them. "Roads Were Not Built For Cars!"