I've had experience with both the inline 4cyl and 6cyl..the 4 does get better mileage..and I didn't need to floor it all the time. The 4 cyl had amuch better front to rear weight ratio for the days when I came upon slippery/snowy areas without hubs locked in. The 6 cyl got 18-19 mpg while the 4 cyl got 21-22 mpg. My Samurais(2) got 30 mpg whether in 2 or 4wd.
I have bought Rangers sinc they first came out..about 10 of them ..all 4cyl manual except for one 4.0 V6 auto, 4WD. My present 4cyl gets 28mpg OTR and 25.5mpg when hauling my teardrop style camper. The 4.0 got 18-19mpg OTR and when hauling an 18' regular camper, dropped to 10-12mpg, depending upon conditions.
My whole post here started with the lament over a truly base model..which doesn't seem to exist in today's inventories. All the electric doorlocks, electric windows, power adjust seats, auto transmissions, power tailgates, electronic 4WD engagement, fancy rimbellisher wheels, power sunroofs etc, etc only make a vehicle less, rather than more, dependable. Just that much more stuff to go wrong, say nothing about the unnecessary added weight.