We are dealing with some similar issues these days. Both DH and I would like to go for longer rides with our kids, we have 4.5 yr old twins and a 3.5 year old. We are not sure how much longer this is going to work but...Just yesterday we went on our first long ride on the W&OD trail in N.VA (almost unbelievably!) my husband had a single trail-a-bike behind him and buggy attached to the trail-a-bike, also behind him (he is in pretty good shape!). Then we had the other child in another buggy behind me. All three kids took turns on the TAB (the 4 yr olds spent much more time than the 3 yr old), we just had them switch when they got tired or when another wanted a turn.

We will probably get another TAB (to go behind me) and keep the one buggy (behind DH) in case someone gets tired. But we may also consider getting a double TAB and eliminate the buggy all together. My DH said that they definitely DID help him when they pedaled up hill. Now, no mistaking, it was not a fast ride, but we had a really fun time.

And as a sidenote, we did pass a couple on a tandem, with an older boy (6-8yrs?) on his own bike, but attached to the tandem somehow (they must have some connection available, his front wheel was lifted off the ground), and then they also had a buggy attached to his bike behind them with a younger child. I was just glad to see that we weren't the only people forced to pull an enormous train down the bike path!