Absolutely....it wouldn't be a Frost/Miller wedding without a few kids running around!
There will be parking signs. You will park at the bottom of the hill and be shuttled up the hill to the venue.
If your invitation says 'and Guest' then yes! Otherwise we'd prefer it were just you.
Cocktail attire....A small step above semiformal though not as formal as black-tie. No need to whip out those heels unless you love 'em!