An interesting quote. I know that for many women, when a younger guy suggests that he likes "older women", they're immediately turned off by the remark. I would presume that there is no other entendre for a "Mrs. Robinson" analogy than the whole "older woman" statement. As with most things, I'm sure it has a lot to do with the manner in which the sentiment is delivered. However, I think its very cool that you like his fantasy. Especially from a 35 year old's point of view, anyhow.
I'd chose the 50 year old woman over the 25 year old woman more times than not. But, as this isn't a thread about age, I'll stop there....