My l'il sis did what was her longest ever ride at that point on what started as a 2annahalf (one was slipping) speed Kingpin in 2010. It was 1annahalf speed for the last 10 miles. A 35-odd mile night ride, including Comedy Off Road section across Skipwith common, that my then 8yo led out from York Rally which featured a fairly impressive halfway picnic at Uranus with bonus marshmallow toasting on a Kelly kettle using spare spokes, and which about 30 cyclists of various levels of ability and experience and with an entertaining assortment of bikes turned out for, which still makes me smile when I think about it. It's not all about the bike.
Mind, we were in the LBS within a week getting her a nice Trek hybrid, and a couple of weeks later her partner (for whom it had also been a personal best distance) was in there buying one himself to replace the slick-shod hardtail he'd used, and between them they now have 6 bikes (I think) and a range of brevet cards and medals ranging from the pink 50s to an LEL one...