I travel to Missouri often and they are way more firearms friendly than Texas.
Missouri is an open carry state, but municipalities can ban open carry by local ordinance, so be careful if/where you open carry.
Busses are off limits. Police stations are off limits period. Other than that, pretty close to the same.
The only sign requirement is smaller than Texas (11x14 with 1" letters) and no specific wording requirements other than something stating concealed carry prohibited.
The big thing is if you are caught carrying in a prohibited place, they just ask you to leave and no penalty unless you don't.
The link Teamless posted is a good resource.
Enjoy your trip!