8 hours driving every drill, that's fuel, increased servicing, tyres, depreciation on your vehicle, your own time, multiple times a month, 1000/2000 + miles a month, 12000/24000 miles a year. 4 hour drive is going to be a risky endeavour after a drill where you've been flogged, with little rest. Hell of a commitment.
I currently fly in and out to work. It's a 3 hour drive to the airport. I do 8 x 12 hour shifts at the mine, take two 60-90 minute flights, pick up my car at 2030 and get home about 2330. I quite often struggle during the last hour of that drive. I'm doing that rotation twice a month.