Yes it is. You can request (at no cost) a big sleigh and they will push you around. Senior citizens can also request this if they have troubles walking in crushed ice. We've requested it in the past for our Grandparents.
I think it's possible to get inside, but it might be hard to navigate due to the crushed ice surface. I would call the nice folks at ICE Castles. They are very courteous.
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