He's already filed and plans to run for both offices simultaneously. Being a Texas resident (if you actually are), I would think you would know that LBJ got a law passed to let him do this and it has stayed on the books ever since.
Ron Paul has indicated that if his campaign becomes hopeless, he expects to go home and run for the House full-time.
We've already carried him farther than he ever expected. He's willing to go forward as long as there's a chance. Expect him to be in the first three races (IA/NH/SC), probably the first five. If he has any chance of getting the nomination and our support is strong and growing, he may continue on. But if not, I expect he'll end the national campaign and focus on his House seat.
As for a 'retirement fund', that's just silly. It's against the law. There are various clever ways to use such funds as PAC money but Ron Paul is one of the last politicians who would ever do that. I expect he'll pretty much spend everything we give him on the national campaign. He knows we'll support him in his House race as well.
The new GOP sacrificial lamb is Chris Peden. Ron Paul's last electoral victim was the Dim, Shane Sklar.