At my seasonal site, I level side to side first - using 2x8 boards under its wheels. If one side needs to be higher, I use another 2x8 board (screw them together to stop board slippage). Once level side to side, I then level end to end - using a 2 ton bottle jack. If wondering, I do NOT lift the TT wheels off the ground. Might raise the TT approx 2-2.5" - to take approx 80% weight off its tires / leaf springs. And, I use auto jack stands spaced 6 ft apart down its frame rails. These axle stands are on thick patio stones. Due to trailer frame height, I'd use 12 ton jacks next time. Thus, creating more support area with less reach. Before buying 6 ton or 12 ton axle stands for your seasonal site TT, do measure the jack's reach. For picture of my TT's setup, surf:
http://i178.photobucket.com/albums/w...e/100_0696.jpg
Hope this helps in your research....