My old ute has a thermo fan. Came that way when I brought it. It has stopped twice in the time I have had the ute. Out at wombat State forest. Just turned the heater on , with fan as well and that was enough cooling to stop the motor from getting too hot. Travelled from Wombat forest to Belgrave Heights. It does though have a big radiator that is a Holden V8 radiator. One other time was a wiring issue. Just bypassed the thermo switch and all was good. Now if you ran two smaller fans that would be a good set up. Be damn unlucky for both to fail. With one and the heater going I`d think you would get by ok.
Cheers Hall