Can you visit other beaches if you're a WDW resort guest? Not the pools, just the beaches. If not, exactly where are you allowed to go when visiting a resort that you're not staying at?
Not sure why you would want to visit other beaches, you can not swim in any of the water.
When visiting resorts you can dine, have drinks, shop and just check them out in general. Sure, you can look at the beach, walk through the sand for a minute.
The Poly beach is a great place to watch Wishes and the Epcot resort area beaches aren't bad to watch illuminations - so that is a reason to beach hop.
You can use the marina's at any of the resorts to rent water mice, etc if your (value) resort doesn't have it too!
yes, we stayed at contemporary and went to poly . there were hammocks on the beach near the pool. we enjoyed having a rest there after having dinner at the ohana place.