.duncan the cycle expeditions are done pretty much the same way as walking expeditions. Groups are expected to camp and carry all their own gear (panniers etc). Daily ride time is meant to be 6 hours in the saddle covering around 50k per day … for various reasons (poor nav', being lazy, etc) I've seen groups out for 12 hours. One group of lads from a very posh school once took 7 hours to ride 9K 😯 over part of the Sarn Helen.
The hardest part is making sure atleast some of the group have a certain amount of mechanical know how … buckled rear wheels is the biggest problem due to the weight they're carrying and (often) poor riding.
Finding 4 day routes that'll keep they away from temptation can also be tricky … Scotland and mid Wales tend to be the prime areas. Wide open spaces and no shops!
Stuart