having just arrived by my eighth different route from the UK, i think i may have cracked it. from my local airport to Amsterdam, onto Panama. Both KLM. civilised times, 90 minutes connection.
Look at a globe not a map, to get a true perspective.. overnight in panama, at a half USA price hotel, (basic, large room, clean) with the best pickup bus service i have ever encountered. go to a designated tour desk on the way to the exit, wait a few minutes for other arrivals, then escorted to the minibus.
luggage checked right through to belize, next morning mid morning flight to Belize city on COPA.
the total flight time less than many alternatives. certainly the most relaxed schedule I have had. and very competitive price. next time , a couple of nights in Panama to see the Canal.