If you're using 3/4" particle board, you should be fine. Make sure you don't route too big a hole, and to leave the cutout corners rounded. Hmm, it also depends how big the CP is, and the support it rests on; best to have at least 2-4" wood above and below the TB, and have the cp rest on a strong support all the way around.
Plywood is much stronger, though; you could get away with a little less of everything. [shrug]