I think that alot depends on what you are doing with the top. Are you just staining it and calling it good? Are you tiling the top? I assume you are triming out the front and sides with some kind of moulding to hide the gap. Why not just block on the corners on the cabinet to support the extra load of the overhang? It should be hidden by the trim when closed and it would certainly prevent warping over time, even though plywood is more resistant to warping than board stock. I guess, my questions would be....what exactly are you going for? I don't like the idea of liquid nails, because if your freezer goes bad, it's a gonna be a b*tch to get the top off of the lid of the freezer. I bolted from underneath up through t-nuts on the top, but if you are just staining the top, that wouldn't work.