Support under the smoker

I've never been in a competition, but I'm planning to do one. My smoker is not on a trailer, but it is a heavy offset. I'm picturing a competition where we're set up in the grass, and it rains. I'd never get that thing out of the mud.

Is there any problem laying down a piece of plywood under the smoker? Could be a fire hazard. Any other ideas?
Thx, JJ

Steel - good idea, thanks - I'm not real bright.