you have to travel 34 km thourgh the sand dunes to reach to the inland sea "KHOR AL UDAID" but, the problem is x3/x5 or even x6 can't reach there w/o getting struck x times. (i know, landcruiser in not the only 4x4) so, my advice to you is to go in a group, or try going with one of the trip operator like, gulf adventures or something like that and see if you can reach to the point we are talking about.

cheers.