If it was me, I would take that log back where you found it. :wink: But, since it already followed you home, you don't have much to lose by trying to make something out of it.
Palms are closer to grass than to trees. That makes the "wood" somewhat of a challenge. I've never found a palmate (aka fan) type palm that was interesting. Many of the pinnate palms have beautiful color streaks in the outer inch of the trunk and you can get nice pen blanks from that. Especially alexander and royal palms.
If you could get the rootball, that might be worth cutting up and casting. I've never done it, but I've seen work by other turners that have and they created some beautiful bowls and vases from the stuff.
The interior of palms (once you are past the outermost 0.5" - 1.0") is very wet and spongy. In my experience it will deteriorate as it dries. I think you would want to try and stabilize it before casting it.
Ed