One option would be going to your local home improvement store buying a sheet of 3/4" plywood have them cut two pieces to size, glue them together and screw them down to your HF box.
Sometimes you can find blemish tops in their stores for less.
Grizzly tools also sells butcher block counters as well as Ikea in varying grades and thicknesses. Gotta watch Ikea though as some of theirs are not solid wood.
For a nicer look use the 3/4 plywood for a base and put some pre-finished wood flooring on top.
You are talking pretty basic wood working skills.
Screw and glue the two layers together oversized.
Cut a peice of cardboard to fit your box top.
Use the cardboard to lay out your cut lines on the bottom and cut with a cicular saw with the top upside down.
This will keep the blade from splintering the edges.