Binion's validation machine (one of them at least) is at the end of the cashier cage and is fairly well signed.

I think meter parking ends after 8pm if you care to visit later in the evening. There was quite a few spaces available on the street when we visited this past Thursday and Friday night. We parked on Ogden (by 3rd Street), a block north of Freemont but if you circle Ogden, 3rd Street, Carson, and 4th Street you probably should be able find something.