The best off-road tours are available in deserts of Iran. For a short trip you can take two-hour tours in Mesr Desert.

Also, some tours are available for 4 – 5 days:

Passing through villages and oases in the heart of Iran Central Desert such as Farahzad, Aroosan, Koreh gaz
Visiting Naiin, Anarak and Meybod towns.
Exploring elegant historical villages such as Kharanagh, Anarak and Mesr.