Re: another wrinkle
Nobody lives in that state
Presumably you mean neither of the parties involved lives in that state. I assure you, someone lives in that state. In fact, enough someones for them to have legal districts, which is what matters here.
What doesn't matter is the fact that the parties involved don't live there. The district where the crime is committed is the venue (in this case). Really, I don't understand why you think it might be otherwise. Courts don't exist for the convenience of defendants, victims, witnesses, or (in civil cases) plaintiffs; they exist to determine justice.
If you and the Mrs and youngin robbed that gas station during your cross-country trip, and were subsequently caught, what venue do you think you'd be tried in? Or if the other woman robbed it, and you witnessed it, where do you think you'd be called to appear?
I don't think it matters, assault is pretty much against the law across all 50 states?
Many things are against the law in all of the US states. That doesn't mean venue is irrelevant. States have many differences in how they deal with common crimes.
Murder is against the law in all 50 states, but there's a big difference between being convicted of it in Massachusetts and being convicted of it in Texas.