I had a flat on my horse trailer once. I had no spare and no jack but I had firewood in the back of my truck. I ended up backing the flat tire onto blocks to get the good axle off the ground .... then wedged blocks in between the frame and the axle with the good tire. I then drove the good tire onto blocks to get the flat off the ground. I removed the rim with the flat tire and drove home on three good tires..... it worked.
I think the best solution is to buy a leveling kit for my RV and use it if I ever get a flat tire on it.
