I take two 2x12s, each is 5 ft. long. They are heavy, a bit cumbersome and I carry them in the bed of the tow vehicle. The are stored in the TT storage compartment when not in use.
They work great.
I simply back into the campsite and when I am satisfied with TT position, I set the boards next to the low side tires. I pull forward five feet and slide one or stack both of the boards behind the wheels as needed for level; Then I back up five feet. Easy peasy.....:)
Yes, as I said, they are bulky and a bit cumbersome to store but when I am done, I have both tires sitting squarely on a one foot by five foot wooden platform, with up to 4 inches of level.