The Townie, however, was a bit of a problem. We were skeptical about putting a Biker Tutor on it. So a few months ago, I contacted the inestimable (that's a good thing) J.C. Lind of Chicago regarding ordering the Roland Add+Bike, because he's The Guy if you want to buy that product in the United States. The Roland Add+Bike is a special (very, very beefy) bike rack which has a connector for a matching trailing bicycle; a child's seat can be attached to the bike rack simultaneously. We went with a GMG. There are some aspects to the installation that are a little dodgy. In particular, this particular seat and rack combination requires it to be mounted quite close to my seat on the bike (this is partly an artifact of the Townie's very laid-back geometry). The good news is that A. does fit in it with me on the bike and I'm never in any doubt about her doing anything I don't know about, because she's as close as if I were wearing her in the Ergo.
The Townie is quite a long bike front to back. With the trailing bike, backing it out of the garage is very tricky. However, I am quite optimistic that this setup will let me take both kids out on short runs (store, school, playground). I have the front tray for cargo; I still need to find a pannier that will attach to the rack (big round bars, which is an issue, and also there's some conflict with the seatpost for the kids seat).
Best of all, the trailing bicycle on the Roland is really easy to take off and put back on. It does not have the double redundancy of the Burley, but it's quite impossible to imagine this attachment failing, so I don't think it needs it.
T. has been really wanted to "go growee!", which means, go to the grocery store on the bikes. His Kettler Sprint balance bike is way too small for him and has been for a while. I kept hoping he'd be willing to adopt one of the regular bikes with pedals, but he experiments with them only briefly. When I realized on Thursday that A. was older than T. was when we bought him the thing, I broke down and found new balance bikes for both of them. We got the Glide Bikes in two different sizes. R. put them together today, and they have a couple of interesting features. (1) Foot posts in approximately pedal location. I have no idea what the kids will think of those. (2) Foam filled tires. This last is _awesome_ because it's really tough figuring out how to get air in the tires of these things; you basically need the compressor and its flat attachment. None of the elbow fittings will fit in the space the plastic spokes allow. (3) They are _light_! Incredibly light compared to the Kettler Sprint. But other than a relatively crappy seat, they seem well made and the paint job on them is excellent (this matters more than you might realize until after they've stayed wet for a while unexpectedly).
I think this means we are officially ready for spring. All the tires are aired up. We have appropriately sized kids bikes and the adult bikes are both set up for two kids, 1 adult and cargo.