Towing

I'm pulling a 16-foot Coromal pop-top caravan. It’s not heavy and not loaded. The car is a 2002 Mitsubishi Pajero Exceed petrol which seems to rev at a constant 3000rpm, even on open and relatively flat roads. It drops back when level or on decent. Is it normal to rev at 3000rpm, and constantly vary what gear it’s in? It’s making fuel consumption higher than necessary.

I retire shortly, and wish to travel Australia as a grey nomad. I want to purchase a tow vehicle and probably a hybrid camper. The campers seem to have an average max loaded capacity of around three tonnes. What (second-hand) tow vehicle would you suggest? I'm thinking Ford Ranger because of popularity and therefore availability of spares without the Toyota price tag. If I'm on the right track, what year and model would be the one to aim for? I won't be doing any too-adventurous four wheel driving.