There is no parking at Pioneer Hall (except for golf carts). Everyone has to park at the front and take a bus there. Give yourself enough time to check in at the gate (line is often long), find a spot (occasionally we have been sent to an overflow space), wait on a bus, and get there.
It is not walkable. For one, it's a busy road with RV's, buses, and golf carts but it would also be at least a mile, if not longer.
The easiest - and most scenic - way of getting there is boat from MK. The boat dock is right near Pioneer Hall. Just in case it lines up with your plans to use that instead.
Enjoy the show!