We had an estate car where the rear seat split in a 2/1 seat configuration. the 2 seat part could be laid flat, the tandem, without front wheel could fit in, semi stood up, in fact we could also fit in a solo alongside the tandem also with front wheel out... the space behind the rear single seat was taken up with bags and packing etc, child took up the single seat.
I stand and rejoice everytime I see a woman ride by on a wheel the picture of free, untrammeled womanhood. HG Wells
We have been very happy with a Thorn Voyager childback tandem, from the time our children were 4-5 years old. We used it for school runs, but also for camping holidays. Thus, we took it on Dutch trains, on UK trains (with some difficulty) and on German international trains. On the camping tours we towed a two wheel luggage trailer with it. I think in your case taking the bike is just taking a very heavy and big toy, something you cannot really do on a cycling holiday. Our children never complained that we did not take their children's bikes, until they were old enough to ride them themselves on tour (i.e. from about eight). And yes, take the trainer wheels off as soon as you can.
Last edited by willem jongman on 24 Nov 2016, 1:10pm, edited 1 time in total.