Hi Pete & Sam,
Welcome to the forum. I'll try and answer the questions direct and short.
1) If you import you get pot luck, but buying from a deal at least you can see it first and go through it.
2) 3.0 for a camper/conversion. As i found the 2.4's gutless uphill
3) does not matter which year. I found that the 3.0L on the 2002 - 2005 great it's a Lexus non interferance engine so if the cam belt goes your engine does not.
4) YES that's a must be done over in the country.
5) Toilet, fridge and heating.
6) has it had a new cambelt & when was the last service.