Do you think super-sizing the kayak carts would work for a 55 gallon drum? I have plants 1/10 mile from the nearest spigot that need watering. My plan would be to put larger wheels on the kayak trailer. There would be 1x 90 degree union and 2x 135 degree unions that form the side braces and rests for the barrel. These would be tied together by the axle and cross bars (just like the kayak cart). A drawbar might be fashioned from a long member with a cross union and T union where the end was pounded flat to allow a bolt with washers and wing nut as a hitch pin.

Would 3/4" conduit be strong enough, or do I need 1"? 55 gallons of water will weigh over 400 lbs. The terrain is fairly flat but there are slight rolling hills and some bumps to overcome.