Easy
Just lower the front of the trailer as far as possible, block up the rear, and raised the front as high as it feels safe to or until you can paint where half the boards were. WEhen done, reverse the process: put the boat back down again, then raise the front of the trailer as high as it will go, block up the front, and lower the trailer. Now the front is floating on the blocks and you can paint the rest of it. Good luck.
