Recently, I read The Teaccher's Grammar of English by Ron Cowan.

There are some rules about Quantifier Floating.
I understand most of them, but I really don't distinguish which sentences are grammatical or not.

Your mother wants all of her sons to go to college. <-I got it
*Your mother wants her sons to go all to college. <-I got it

How about the following sentence?

Your mother wants her sons to all go to college. <- grammatical or not?