Hualtuco or Zihua: which was your favorite beach town?

Better learn to spell Huatulco first.
Unless things have changed since we were there, there is no beach town called Huatulco. It's 8 or 9 bays stretching over a fairly large area. La Crucecita is the largest town....purpose-built to service the resorts of Huatulco, so no "history".....and is not near a beach. La Crucecita is much smaller than Zihua and offers far less services. The other places are closer to the beaches, but are very small; hardly "towns" at all.
As others have said, without a vehicle you'd be pretty isolated.