Hi
10w40 Semi is the way to go.
Milners and Roughtrax sell it, I think Roughtrax is the branded Toyota stuff as well.
6 litres.
I def notice a difference after an oil change, so I aim for every 5000miles.
Oil costs £21, filter about £5, so cheap enough to make it more frequently.
I have changed the diesel and air filters annually, but if its all road use on UK fuel I wouldnt bother with either, just spin the air filter round.
Diff oils are another simple job (rear is really easy, but front does require some contortion and a couple of foot of pipe so you can refill it from above.
Gearbox oil easy to take out (and well worth doing) bit slow to refill though as it has to go down the dipstick tube. (asssuming its auto). This is important to do as it lets you check that the 'box isnt contaminated with coolant from the rad.
Rad top up - dont add water or blue collant, use Toyota red, again Milners or Roughtrax.
More info than you wanted......
Cheers
Pete