Jack for trailer to change tires?

Thanks guys. I just got back from a trip to Academy and Walmart. I got the locks for my coupler and hitch at Academy and I got a rechargeable drill with two battery packs, a 1.5 ton Scissors jack, a 4 way lug wrench and a deal that looks like tennis balls on magnetic based rods for lining up the ball with the coupler. it says they extend 42 inches so I hope that is enough to get them above my tailgate. Your suppose to put one on the hitch and one on the coupler and back up till the balls almost touch. That is suppose to put the ball right under the coupler. I shall see.