I have adopted the page, and I have already provided some information. I will be glad to return the page to either Dan or Boris, so they can mantained or totally change it. Just let me know.
a taxi should not be more than 20 -25 US $ (maxmax)from downtown to Valle de Zongo (2005 we paid 12 US $ from El Alto). You don't need a jeep to get there.
Getting back - don't count any pulic transport back in the afternoon.
There is a ward for Cobee (electricity company) right across the mountain refuge at the reservoir - he can contact one of his buddies at stations further down in the valley who have pickup trucks - they migh be convinced to drive you back to El Alto for 20 -25 US $