Jacking and tire replacement

When I want all 4 tires off the ground I lower the front as far as I can and place 2 jack stands under the frame a few feet behind the rear axle with enough blocking to get them as high as possible. I then us 2, 6 ton bottle jacks under the frame in front of the axles to raise the trailer. I keep the landing gear lightly loaded as I raise the front and even use it to support the trailer as I reset the jacks when they run out of travel. Once I reach the desired height I place jack stands under the front of the frame. This has let me do anything I needed to do the the suspension or tires. 6 ton bottle jacks take up rather little storage space and can be found at Harbor Freight or similar places rather cheap.