Do what ProfDanT139 does :
Rig a broomstick to hold a water jug .
We dry camp frequently .
We carry 3 of the 5 gallon coleman blue colored water jugs .
I took one of the coleman screw on spigots and modified it so that it had a 2 foot garden hose affixed to the throat of the water jug .
I got a VERY large Carabiner and I loop that through the 5 gallon jug .
I took a sturdy hardwood broomstick and installed a hook on one end .
I place the other end of the broomstick on the ground .
I rest that end of the broomstick against the arch of my foot .
I hook the hook through the Carabiner/Jug .
I then tilt the stick up with the water jug hanging from one end .
The jug is now above the trailer tank fill , being held by the broomstick .
I insert the garden hose into the TT water tank fill .
Much easier than holding 5 gallons up with my arms .
My description is poor .
However , I anticipate ProfDanT to be along anytime now with a slide show AND a YouTube clip showing this process ...