Phillip,
Congratulations on the new Cruiser!!!! Here is my two cents...
Talk to the PO and ask him lots of questions. Ask him if he thinks it would make the trip, would he attempt the trip if it was still his, are there any know issues that would concern him, etc.
I agree with
yotadude520 driving it home would really create a fun memory and a great way to "bond" with your new girl

and 300 miles is not too far.
Do you have someone to go with you or are you on your own? I am not sure what truck you have access to that has a 5k capacity, but if you have a buddy that can go with you, I would drive a truck up to Birmingham and try to drive the FJ40 back home. If something happens on the way, you can rent a trailer and limp it home. You also can rent a Tahoe or Suburban for the trip. They have a 7000 lbs tow capacity.
Another option is to rent a tow dolly. You would be way under the 5k lbs with a tow dolly. I would pull out the rear drive shaft so the rear end is rolling freely. 300 miles pulling a FJ40 with a dolly seems very doable in my book!
That being said... There is no shame in having it delivered. $400 is a small price to pay if the shipping company is reputable and insured. I know how hard it is to make time and pull the resources together to go and get it yourself. You probably would spend $400 in gas and trailer rental doing it on your own.
It just depends... how big of an adventure are you up for?
I'm off in the summer, If it were summer time, I meet you in Birmingham and road trip it with you!!