[willy]

You can go into your local wally mart auto dept or similar and buy two, or if you wish three of the heavy duty auto jackstands, they are adjustable. I bought four a couple of years ago for 17 bucks apiece.
Use a bottle jack or similar on top of a block of wood or something to give you the height you need and jack it up the distance you need to clear your engine plus a couple inches for any settling that may happen and put your jackstand under the trailer rails right behind the axle.
You can also do the same to the front of the trailer to give you the height and slope you want.
If you are on a substantial slope be careful and secure it so it won't roll or tip somehow.
The trailer will not fold.
Or just find some pieces of wood or concrete blocks and use your vehicle to pull the trailer wheels up on them, should give you a few inches of clearance