Is the beach accessible for a rolling walker?

Yes. There is a long "boardwalk", which is essentially a ribbed, rubber path that takes you down to the beach to set up where you want to sit.

There is a mat. But once you get off of it it's all sand

Yes it is they have a large mat like walkway all the way to the beach.

Yes and the sand isn't very hard to get through.

Yes, there is a nice rubber mat on the beach that can be used for a wheelchair or Walker with wheels