1st u hav 2 take saudi arabia transit visa den just proceed via road..
go straight from salwa road... once u pass qatar border and saudi border go straight u'll find 1st roundabout take left from r/a and proceed strght some 100-200 km (not sure with the km) to uae border. thats is ur dere.. i thnk d border is @ abudhabi... 

tip: start early morning....