You could do: JER-LGW-MAD(overnight layover)-TFN(same day turnaround)-VLC(overnight layover)-LGW-JER, totalling 240TP for $395.
Obviously not including the hotel costs and overall longevity.
Add in the LON-JER (paid) r/t and you could add another 10/80TP depending on the booking.
Not much ground time (pretty much sleep in MAD, morning in VLC), but an easy 250TP+ earning for a weekend for £320/€340/$395.