You can use Woodland Scenic's "Scenic Cement" and spray it. I have done it and protect it a lot, and dries flat too.
I have spray the table to attach the flock as they recomend in his Scenic Manual and now the flock remains perfectly without becoming hard, what I like a lot.
A very good option, but more expensive than the PVA, of course, but with a better result, IMHO.