Sorry I missed the original thread on this. I thought I’d add a couple things for others looking at this idea:
1) re: Arlington Spraygrounds — Lyon Village park is great, but Hayes Park is more convenient to the Custis, less crowded and has bathrooms — just take the Custis West of the Italian Store (yes, you have to contend with the S-curve), and get off at the “Lincoln Street” exit (I think it’s the third one). Take a left at the street and Hayes Park is just over the bridge over I66.
2) Other suggestions — just ride around the streets, especially downtown and find what you can find. We ended up doing that yesterday (pre-rain) and discovered a really cool fountain on Penn & 19th (by Founding Farmers). In Arlington, there are parks hidden in basically every neighborhood — sometimes we just pick a restaurant, map the parks on the way, and try our luck. We’ve found some great gems. If your kid likes speed, biking through Fort Myer and down the hill in the cemetery is AWESOME.
3) Getting to Arlington — I think the 14th Street Bridge is wide enough for trailers, though adds significant mileage if you’re headed West. Depending on where you’re going, you can take Memorial Bridge, and either cross the GW Parkway (VERY carefully, of course), or continue on Memorial Drive to the trail by 110, passed the Iwa Jima and into Rosslyn.
4) It sounded like one of you is a stay-at-home dad — my husband is too, and he bikes everywhere with our almost-2-year-old (mostly around Arlington). There’s a network of SAHDs and regular playgroups. If you’re interested, PM me.