I like to use an auxiliary planer bed with my lunchbox planer. Mine are sections of melamine covered particle board, shelf material. They have a smooth, durable surface and are just about the same width as the planer capacity. I like my planer bed to be long enough that the infeed & outfeed sections are as long as or longer than the stock I am planing. This provides good, level support of the stock as it passes the whole way through the planer and helps minimize snipe.
For the longest one, I have to put legs under the ends to support them, but most of the stuff I plane is less than 3' long, so I use one of the shorter ones. I keep them waxed, with a paste wax, so they are nice & smooth. The only drawback is that the scale on the depth gage will be off by the thickness of the auxiliary bed, but I always measure my stock with calipers anyway, so I don't count on the gage.