...You shouldn't ever leave home without a small, portable jack...
That's a good point. It may also be helpful to note that you may have more equipment than you know - the typical tire-changing jack hiding somewhere in the back of the tow vehicle can lift far more than the tongue weight
of the trailer, and may (depending on height range, shape of the jack top, etc) be useful in roles other than that which the tug maker intended for it. In a pinch, interesting things can be made to work for temporary use, especially if one is careful to stay out from under (or beside) questionably supported stuff.