No guarantee, but I have an idea. You do not describe the sides of your trailer. I have a 5x10 with removable stake sides. If yours is the same and you are willing/able to do without the sides, what you would need to do is just to get the mower deck high enough to clear the fenders. You might build what would amount to solid, well supported ramps that you could drive up on to get the needed height. Certainly it would not be an ideal solution, but could be functional until you have a larger trailer. You could use the space between the ramps for storage, although it would not be accessible while the mower was on it.