Best method for walking with a 21mo and nearly 4yo?

[MegBusset]

Have been using buggy + buggy board for yonks with the DSes (21mo and 3.11) but DS2 is now refusing to sit in the buggy without huge protest. We have to walk to and from preschool (10 mins down quiet footpaths) twice a day. Just wondering what the best option is if we ditch the buggy:

1. We all walk - this will take ages as DS2 loves to meander, more to the point DS1 always knackered after preschool and will whine to be carried all the way.

1. I get them both micro scooters - the expensive option. But is 21mo too young and will I end up carrying the scooters all the way?

1. Balance bikes?

1. I fold DS1 into the buggy, let DS2 ride the buggy board and ignore the judgy looks?

Just looking for ideas really, TIA!

Or is there a bike trailer that will take two DC? i could cycle easily enough...