Thanks Phil and Bob for all the tips and suggestions. I am aiming to do the welding early next week. I love being off on holidays.
I'm thinking I will sandblast the frame and then paint with POR. Layout the new sheet and drill my holes for plug welding. Then go and mark the spots on the frame and grind those down. Once it is welded on I'll use a flap wheel to smooth out the welds. Then flow the POR along the seams to try and get it all sealed up.
Bob I've got four different work tables in my shop. I've got a metal clad bench. I was given a 4'x8' home made table with 3/4" plywood on top. I use this one for all my welding needs. Then I have a set of Cnd Tire saw horses with a piece of melamine coated desk top. And lastly another pair of Cnd Tire saw horses to use as needed. They have probably been the most useful things I've bought from Cnd Tire in a long time. Currently on sale too.