Ad far as tools needed, barrel nut wrench, action wrench or barrel vise and go/no-go gauges. Parts you will need, bolt head and possibly a magazine. You may be able to adjust feed lips to work properly with different cartridge. You will need to check if the Model 11 is a standard(small) shank or large shank before purchasing a barrel and I think some of the WSMs came as controlled round feed, so you will need to verify that also. If it is controlled round feed, you may have to do some modification to the new bolt head.

It is pretty easy to swap barrels, especially once you have one under your belt.

I am actually wanting to convert one of mine to 260 Rem., or if I can just find the complete rifle in 260 I would just do that.