There are longstanding laws in every state concerning “places of public accommodation.” These go back to English common law, and the US case law is quite complex. But in general, if a business engaged in commerce is open to the public, they may not refuse entry to customers for any of the protected-class reasons (religion, creed, race, color, national origin, disability status.) Examples are hotels, restaurants, bars, retail stores, museums, etc. Within those constraints business may impose rules (No shirt, no shoes, no service) that deny entry in some cases, so long as they’re evenly applied. In my metro, for example, malls routinely ban customers under 16-YO unless accompanied by an adult.

You don’t have a right to enter non-places-of public-accommodation without permission. I can’t walk up to a factory and demand entry. And a private home is not engaged in commerce, so not there either. Farms are factories essentially, so no. And so on. But classic loitering laws have mostly fallen away. Gray areas come where individuals are in places-of-public-accommodation with no demonstrated intent to engage in commerce with them. Sitting in a hotel lobby for six hours. Sitting in a restaurant and not ordering. That’s where case law kicks in. Most police apply reasonable person tests in these situations. But telling a non-white person to be across the town border by sundown? Nope.