Tony
On a truck as new as that I wouldn't even think about 35" wheels...not only does it require some serious body cutting but as you say, it puts a horrendous strain on steering and suspension - you would bollox your nice new truck for ever more.
And as I said, on that Mk IV you have fixed hubs, so you can engage 4WD at any speed.
Did you bottom out or something? What conditions did you get stuck in?
Best advice for a good mix of on and off road suitabilty would be as follows:
1. Remove side steps.
2. Remove towbar.
3. Make sure your nose isn't too low - if it is, wind up the torsion bars until its about 3cm lower at the front than the back (measured from floor to top of wheel arch).
4. Fit 31" x 10.5" tyres on to 15" wheels - 16" tyres cost quite a bit more - you can fit a whole range of wheels from Toyota, Mitsubishi etc...Jap 6-stud and PCD is fairly standard (lots of threads on here)...different offsets will affect whether the tyre sticks out of the arch or not, but its the largest size you can fir without getting a hammer out. General Grabber AT2s or Kumho KL71s are good all round tyres.
5. If you must, fit a 2" suspension lift kit....but TBH the above should get you a very long way indeed.....