I rode this trail with my girlfriend on a Friday evening starting from around the intersection of routes 1 and 120, in Alexandria, VA and it was wonderful. Here is the link to my ride stats and map generated by my Garmin Edge 500 computer: http://connect.garmin.com/activity/106009753

I think because it was Friday and in the evening, there were fewer people on the trail compared to weekends and the more northern section closer to D.C. (which generally has lots of varied traffic - walkers, kids, pets, super fast bike racers, and so on). The last two miles heading into Mt. Vernon are mostly uphill and some areas like the last few hundred yards reached about a 7% grade, so drop to your lowest easy gears and keep peddling! The 0-mile marker is located as you enter into parking area slightly obscured by trees from the visitor center where you can buy refreshments and use the rest room (highly recommended). Along the trail you will find several other "sanitary" facilities for mother nature's call, but the two we visited (one traveling south, the other on our way north) were a bit stenchy in the hot summer weather.

We loved the steep hilly inclines of the last three miles because you can pick up good speed to the point that it makes getting up the next hill a lot easier if you can keep your momentum up. Personally, I found it easier to climb the hills by keeping my cadence closer to 100 so that the bike did more work than my body. It takes a lot of shifting, but it pays off. The varied surfaces combine greatly different scenery as you ride along the picturesque Potomac, over boardwalks in swampy sections into densely wooded areas, and through upscale neighborhoods. Old Town is quaint and very pleasant - just watch for peds and cars!

I'd also suggest you eat a high protein diet several hours before riding this one - you'll need the energy. Bring as much water as you can and stay hydrated. A protein bar at the end is a great way to re-fuel for the ride back. When leaving Mt. Vernon, heading north, you'll enjoy the downhill portions immensely as they offer more recuperation time needed to make it the rest of the way...

Two Thumbs Up for this trail!

Rode out and back on a nice but cool fall day. The Washington end was very crowded with joggers bikers and walkers. as we progressed eastward the crowd thinned out to a more acceptable level. Most people were courteous with the exception of the wannabe Lance's who past on turns and with oncoming bikes and pedestrians giving the rest a bad name. With this trail this was unacceptable due to the crowd. Most joggers seemed to be totally absorbed with their ear plugs shoved deep into their ears to the point of not hearing you but they were at least to the sides so passing was not an issue.

This trail is a marvel of engineering. It has variety, goes through dense wooded areas, along the Potomac, around the National Airport, through Old Town Alexandria, across from the National Mall, and has breathtaking views all along the way, from Rosslyn to Mt. Vernon. The trail is well paved, clearly marked and beautifully maintained. There are several rest stations with water (when they are working) every few miles. But, be warned, on weekends it is crowded with weekend athletes, pedestrians, kids, and worst of all, wannabe Lance Armstrongs in their obnoxious spandex outfits, racing along the trail, making it an often dangerous and tricky place to ride. These men and women have little regard for others, display a complete lack of trail etiquette, and speed much faster than they have any business to on such a popular path. I live in Alexandria and make a point of staying away on weekends. But mornings on weekdays are wonderful.