Filling Fresh Water Tank

I live in Colorado and have a new Trailmanor 19/26 that I just love. It's ideal for the backcountry camping I do when hunting and fishing far from established campgrounds.

Typically, I head out with a filled water tank, but after four days or so that water supply has been used and I refill in the boonies with full water jugs I've brought along in my tow vehicle.

That refilling of the fresh water supply in the boonies has proven a bit of a problem, though. I've tried conventional funnels, but they aren't angled so that they work particularly well with the TrailManor's water tank fill spout. If two of us are camping, one can hold the funnel while the other pours. But when I'm alone, the juggling act with conventional funnel and heavy 10 gallon water jugs is difficult.

Does any commercial firm make an angled funnel designed specifically for filling RV water tanks in the boonies with water jugs? Or does anyone out there have any ideas on how to modifiy a specific funnel to work well for this purpose?