The easiest way to transfer your mailbox contents, assuming you are not using an IMAP set up, is as easy as right-clicking the desired mailbox in Mail and selecting “Archive”. This will export to mbox format which can easily be imported on your other Mac by choosing Import/Mail for Mac OS X.
All your settings can be copied to Thumb-drive then dropped into new machine in Library file..
As needed…
/Home/Library/Keychains (copy the whole folder)
/Home/Library/Mail (copy the whole folder)
/Home/Library/Preferences/ (copy the whole folder)
/Home /Library/iTunes (copy the whole folder)
/Home /Library/Safari (copy the whole folder)
/Home /Library/Calendars (copy the whole folder)
I tend to trust Migration Assistant…it’s really pretty good. Get the transfer cable, boot to Target Drive and grab some coffee.