The hall is expansive, but not so much so that it takes more than about 90 minutes or so.to see everything. Given that, not sure if they'd let you come and go within a visit. I agree that calling and asking is your best bet.
I don't believe you are able. You enter through one area and usually exit out through the pro shop. But definitely call to see.
Ticket states date of purchase and I would call to confirm that you may renter after going to lunch. https://www.patriotshalloffame.com
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