Here is the Pool Hopping statement from the member's website:
"Whenever you are staying on your Membership at
Bay Lake Tower at Disney's Contemporary Resort, Disney's Animal Kingdom Villas, Disney's Beach Club Villas, Disney's BoardWalk Villas, Disney's Old Key West Resort, Disney's Saratoga Springs Resort & Spa, Disney's Vero Beach Resort, or The Villas at Disney's Wilderness Lodge, you and any Guests staying with you, are permitted to use most of the other Disney Vacation Club and Walt Disney World® Resort hotel pools (in addition to the pool at the resort hotel at which you are staying) if they are not at capacity."
HH and GCV are not currently included in that policy, but it can't hurt to ask at the resort about using the main pool at HH. The resort is usually happy to allow
DVC members to park at the resort and walk around the facilities. If they have any unoccupied and clean villas available they may provide a brief room tour too.
The HH beach is a public beach, but you will need a Palmetto Dunes parking pass to drive there to get thru the security gate. In order to enter the beach house to use the pool there you will need a HH room key. You can certainly ask at the main resort, but they may not be able to provide access to the Beach House. Anyone can walk to the beach without need for an access pass and can then use any of the public beach access areas, including the access area shared by the DVC resort.
Enjoy the resort.