[Casiopea]

She has too much free time. (OK)
She has much too much free time. (OK)

Iff much is modified it's okay.
Iff much is left unmodified it's awkward.

much works well in questions because its quantity is left undefined:

How much free time do you have? (OK)

The same holds true for negation:

I haven't much free time / not much time. (OK)

Using much as a quantifier doesn't work well:

I have much free time (Not OK)

unless it is itself quantified:

I have too much free time.

:D