I would look into the clear table top plastic that comes on a roll. I have a store that carries all different thicknesses for going over fabric table cloths. I would get a piece big enough to go over the whole thing and under about 3 inches and tape it under the table. You could cut a hole where you need it and maybe put painters tape around the opening so nothing catches. Some Walmarts also carry it on a roll but you could check Joann's or similar as well.
p.s. A plastic shower curtain might work as well?