the VM 2.8 in the jeep is a nightmare in australia , if you want one you will not have to pay much to get one . The big Lcrs 4.2 or 4.5 will tow well , the earlier versions will tell you not to tow in 5th , good advice as the gear cant handle it very long( although you are looking at auto which is reliable , but has a tendency to hunt between gears when on long climbs) . If you use all the power and get a move on you can get down round as low 12mpg , Ive done it with an emergency response unit !
i used a 300tdi 130 defender DC HCPU extensively in australia quite frequently at its GTW of 7450KG , it handled it well , managing 25mpg and cruising at about 100kmh on the flat , slower uphill and quicker down
The tdi engines do require a bit of a rev to get off the mark ( the auto a ZF unit (very good) tends to mask this as you can just boot it and the torque converter does the rest) , noticeable compared with my 110 V8 , which will go from tickover clutch engagement and just press the accelerator to get the amount of torque you require but your then looking at 15mpg in comparison thats why i just re-engined it with a 3ltr BMW TD for european use.

The cherokee tends to be a bit weak in the rear axle bearing area , but the 4 ltr hemi petrol engine is a very nice unit , with a long life. , but again being petrol a bit juicy .