We used x2 trailgators when our two were young.
They worked well, but some tips:
Tighten them up a tightly as you possibly can, otherwise you’ll find your kids overtaking you at very odd angles.
Don’t forget that they’re behind you – got carried away once & flew down a lovely piece of singletrack. I did hear a scream from way back up the track – a bit odd as there hadn’t been anyone there – anyway, got to the bottom & turned around to see if child had enjoyed &, you guessed it, no child. Woops!!
When turning, remember that you’re ‘a long vehicle’. Mrs rig did a sharp right over a plank & deposited child in the burn. Woops again!
On reflection, it’s surprising that our two still cycle 😯