First thing to remember Toyotas are NOT indestructible. If you intend to do a bit of off roading this is where you must have thevehicle fully up to scratch. I have had my after market Turbo diesel now for 12 years and on my third gearbox. I found out that the reason for this is that I have been towing caravans for 8 years and did not know that one does NOT tow in fifth gear. unless you are not straining ie going up hill even the slight incline . if you are towing and want to preserve the gearbox then always go back to 4th on inclines.
If you are going off road then ( and if you have a manual gearbox) be very careful when using low range low forward or reverse. because the ratios are so low and the torque huge you can easliy strip the front diff crown wheel. So maybe take some lessons from an experienced off-roader before going off-road.
Hope this helps a bit
But my Toyo is still going strong despite my hard treatment of it.
One more thing, If you decide to fit an after market turbo ... which I have, then be aware that the 1HZ engine has thinner cylinder walls that the factory turbo engine so if you do fit a turbo I would be fitting a low to medium pressure unit because the 1HZ will run hotter than the factory turbo engine.
Look after your Toyota and she will look after you