Yup. State don’t have any power to refuse directly. Once in a state, a state _can_ deny services and do other awful non-federal regulated practices, but they can’t be denied ‘border crossing’ because US state borders are weak things.
That’s also one of the things that makes our setup very powerful, as opposed to 50 independent States loosely knit together. Momma USA gives a lot of power to its children, but the states remain children for a good reason. It works.