I suspect you really need to consider alternative methods. here. The time it is going to take you to fill, haul, and water every day is going to be pretty high.
I have a PTO pump that recently cost me $119 plus the PTO adapter of $32, and it can pump 9 gal per minute @ 540. The pump is rated to 2000 rpm and will pump some ridiculous amount like 30 gallons per minute. I would suggest the PTO pump route because you'll get those drums filled much faster.
12V pump pumping a typical 3GPM would take 73 minutes to fill 4 55 gallon drums.
My pump running at 540 rpm would take 24 minutes. If I add a 2:1 pulley, then roughly 12 minutes. I don't know that I would try to fill any faster than that because it seems like things would start breaking trying to pump a crazy 30 GPM into drums.
Suggestions: If you live where it is wet, use sprinklers. Invest in enough hose to get you next to the lake, drive your tractor to the lake, hook up the hoses (1 to lake, 1 to sprinklers), crank up the PTO to a reasonable rate, eat a sandwich, read a magazine, or I guess you could go pull some weeds or something productive.
If you live where it is dry, then invest in drip irrigation, get as many 55 gallon drums as you can haul on a sturdy trailer (a whole lot of weight there) and drop the trailer off and quick-connect the interconnected drums to the irrigation and go do something else letting gravity do the pressure work (might want to regulate it too). A system like this should last a long time. OR you can go back to the "get a really long hose" idea and leave the drums up connected to the drip or soaker system, and every day just go down, hook up to the hoses, pump the drums full, then go do something else.
No offense, but drive-by watering that many trees is crazy.