So I see from experiment that it's possible to load a fleet, select distant unload, select the destination province, route the fleet to that province then route it immediately back to a port (NOT the port it started from) and the entire sequence can be carried out (depending on distances etc) in one turn. The fleet will sail, drop off the army then move to the new port.
My question is - is there anyway it can be routed back like this to its originating port? The problem is that dropping a fleet stack back on the originating port is the game code used to cancel the entire route. So I take a fleet in Karlskrona, for example, select distant unload, select target province in Denmark, load it with soldiers, plot a route to the target province in Denmark, plot a route back to Malmo - and all this will take place in one turn - the fleet will leave, drop off the men, end up in Malmo. But if I do all that and try to get the fleet back to Karlskrona then the game simply cancels the entire route. Is there a way round this?