SFO-MCO (routing SFO-(LAX)-MIA-MCO-MIA-(LAX)-SFO) is probably the most cost effective KUP. You'll need to get your ar.e up to SFO in the first place, but could skip the LAX-SFO on the return if you manage to route it via LAX. If you manage to route it via LAX and MIA both ways, this is potentially 600 TPS (540 if terminating in LAX). Costwise, it is somewhere in the region of £400.