We towed a jayco swan for four months around east oz with a current model rav4 4cyl auto.
Fuel consumption was around the 16lphk's sometimes higher.
It was within its factory tow specs, had a hayman reece towhitch with weight distribution bars and was covered by new car warranty.
Seriously, why would I have needed anything bigger. It took us where we wanted and we towed at 90 to 100k's. We actually downsized from a 100series petrol a year earlier as we just didnt need the low range and big size (do now though
)
Later on we sold the Jayco and built a lighter weight CT. We could sit on 120 - 130 and overtake at will. Far faster than our new Prado TD. We did 105000ks and the only issue we had was a knock in the steering column replaced under warranty.
I wouldnt confuse them going slow with the capabilities of the cars. If they were grey nomads some (thats SOME) seem to take some sort of delight in maintaining an average speed a model T Ford would be proud of
For an urban family, where low range is not a requirement, a V6 Rav4 with 200kw would be a great tug for an average CT plus they are a great town car.
cheers
daz