You will want to add the new T-Nuts to the new playfield as step one. They will be 6-32 or 8-32 size and you can get them from PinRestore or other pinball parts suppliers. You can tap them out of the old playfield and reuse them in most cases as well. Just mark where you remove it from on the old field and then hammer it into the new playfield.

I have noticed that the pre-drilled holes on the CPR playfields are a tad small. I like to expand them a bit so you do not run the risk of splitting the wood. Use a new sharp wood bit slightly larger than the current hole. Go slowly and don't go too deep.

After you get the T-nuts in, next you will want to add new GI sockets to the new playfield. Then move over the playfield slide rails.

Next would be the rollover switches. From there you have a choice to make.

1) Unscrew everything and move it over in one big blob. It doesn't let you get everything very clean this way, but it is the fastest and easiest approach.

2) Cut the harness from the coils to move each mech over individually. I personally will mark each wire with sticky labels with a corresponding label on each lug of a coil so that I can disassemble, clean and refurbish each mechanism.

After you finish the bottom, then you can work on the top.

Tips:
Take lots of pictures, from different angles top and bottom of the playfield.
Take the time to clean each mech, replace the coil sleeve, worn plungers etc.
Replace ALL bulbs.

The end result will be a brand new looking and playing machine!

To add to the great post above... read a lot of restoration threads here on pinside. It will help considerably, and take a lot of pictures...