Just to add another thought.... (I have limited Mooney experience/knowledge)
operating occasionally on grass may be different than basing on grass. You
will always have 'bad' grass days on occassion if you base on it. Given the
need to go or get home, you will be sorely tempted to operate on such days
(i.e. mud, soft, or uncut).

Another issue may be insurance if you are basing on grass.

I live on 3400' of grass with trees on both ends and would never consider
owning a Mooney for that reason, even though that would otherwise be my
first choice for a retractable.