The bikes are done, and I'm quite happy with the result. My only snafu arose when I went to install the classic trigger shifters rather than the twist shifters that came with the kit; I didn't realize these use different cables and housing. I actually managed to use some spare shifter inner cables by filing down the end fittings until they were essentially square so they would fit into notch in the shifter. But my hack for the housing eventually failed; I pushed a few mm of housing through the keyhole notch in the shifter and then pushed it up so the notch cut into the housing and held it in place. This actually held up fine for the trip I took with my boys, but finally gave way on one of the bikes right afterwards as the outer plastic stripped away on the housing. Anyone know of where I might purchase just the grooved metal end cap for the housing to fit into the shifter? Or a potential workaround? I know I should probably just buy a new cable, but it seems like a waste of perfectly good housing

Regardless, 34 miles in one day with an 8 and 9 year old is, for me, a ringing endorsement for the 3 speed. Thanks for the input! Now I'm looking forward to getting my hands on one of the old 3-speed hubs at the bike co-op and tearing it down with Dan's video as a guide.