There are no caravans west Glen Helen. These might well wreck a bicycle wheel if you hit one at speed. If the Meerenie loop is too difficult, it would be easy enough to find a ride with a utility or campervan - the road has considerable traffic, say three or four vehicles an hour during the day. Some tourists, particularly foreigners, are unaware of the different qualities of water available in the region. Bore water is usually available freely, at least in cyclist size quantities.
Rain water has a pleasantly neutral flavour.
As it is a rare commodity in a desert, be grateful if it is available, and use it very sparingly. At most TPCC camp sites, bore water is provided on tap. There are also permanent waterholes at Ormiston Gorge, Ellery Creek and Glen Helen . TPCC advises boiling this water. The waterhole at Redbanks is of dubious quality due to tourists swimming and algae growth.