Airspeed of light aircraft about 120 mph, 600 miles are roughly 5 hours.
Hourly TCOs from £100 to £400, so £500 to £2.000 for one 600 miles trip.
Large airport fees excluded, some may charge £200, even £700+ for landing.
For a 5/6 airports trip 600 miles each leg -> £2.500/£12.000.