My record with kids (9 & 8) so far has been BRU-OSL/OSL-LHR-MIA/MIA-CUR and reverse. When I showed the route on a map to my son, he asked: "...but why not BRU-LHR? Is closer..."
Try to explain a Viking fare to a kid

OP route into SKB is too long with a 3yo, for my taste. I would have skipped a couple of legs intra-US, like PHL-MCO or MCO-MIA.