The OP stated in his initial posting that he would consider a Fortuner but will not be able to afford a low-mileage vehicle. Which brings me to a question that may not have a good answer.
If assuming a modern 2.5 / 2.8 / 3.0 l diesel motor (as found in all Jap bakkies and SUV's nowadays) that is always serviced as per schedule by the agents, even after expiry of motorplan & warrantee, the vehicle is driven in a proper fashion and also not including items like alternators and starter motors that will fail - what ( km wise ) would the life expectancy of these motors be?
PLEASE, this is not about your brand of choice as they are all inherently good these days - but a question which should have very direct bearing on the OP's ultimate choice.
It may have been discussed a lot - do not know - but should have interesting answers.
For me - I reckon if you get 500 000 km before the motor needs to be opened you are par for the course. Turbo replacement probably looms around 300 000 km?