Hi Again Bruce,
On Mail...
First Quit Mail, then I'd backup these two Mail folders, by right clicking on them in the Finder, then choose Archive/Compress.
Users/YourUserName/Library/Mail
Users/YourUserName/Library/Mail Downloads
(Could be a different folder here if you chose such in Mail Prefs)
Right click on that Mail folder, choose archive, you'll get everything in the folder, and the folder itself in a file called Mail.zip, move it to a safe place, same for the Mail Downloads folder... only the plist is separate.
/Users/YourUserName/Library/Preferences/com.apple.mail.plist
For Address Book, quit AB...
Files...
/Users/YourUserName/Library/Preferences/com.apple.AddressBook.plist
/Users/YourUserName/Library/Preferences/com.apple.AddressBook.abd.plist
Folders...
/Users/YourUserName/Library/Application Support/AddressBook/
/Users/YourUserName/Library/Caches/com.apple.AddressBook/