Jerry I posted earlier on this thread "under lukester". I was hoping to see what other folks came up with.
Just wanted you to know I did the same thing your attempting on my mobile home. After sealing it up and burying the panels I realized that I created a breading ground for every critter known to man. It turned into a nightmare.
They will seek out the heat from the building and just keep digging under it until they figure a way in. If you try to bury a 2 X 6 they will find a way around it in just days.
YOU HAVE TO CREATE A BARRIER THEY CANNOT DIG UNDER,
Here's what works
Lay down rolled roofing (not roofing paper) about 6 inches in from the point that the siding/paneling will rest.
Extend this outwards...lets say 16-32 inches. (The farther out the better). As a option you can also put rolled wire fencing on top of roofing.
The roofing will keep all the red squirrels , chipmunks ,mice ,out.
The fencing will keep out the bigger critters.
Now on top of the roofing/fencing put marble to golf ball size (round rock) 6 inches or better at skirting tapering off to no less then 3 inches on the outside edge.
If critters try to dig into this (round rock) it just rolls.
Not only does it work but it looks great. AND your weed eater along with your back will get a break.
PS: as stated in the posts above if you make it air tight you have to install vents for the spring/summer months.
If you don't you will have a big mold/rot problem on the bottom flooring of cabin. VERY IMPORTANT!!