Google is your friend, or yahoo, Bing.....whoever.....research all answers to your questions yourself. I don't get paid to practice law, let alone get it right the first time.
http://www.moga.mo.gov/statutes/C500-599/5710000030.HTM
Skip subsection two, that is the LE exemptions.....phht.
Subsection three is the money section if you do not have a endorsement.
Subsection four is the CCW holder exemptions.
Read, re-read, and read again the below.
http://www.moga.mo.gov/statutes/C500-599/5710000107.HTM
The where you cannot go on your endorsement.
You can always "carry" on your own property. Be 21 or older and you are good to go. We "change hearts and minds".....phht.....by being scrupulous in our daily comings and goings with regards to the law. I believe that the only folks we need to "change the minds" of are cops. They are limited, constrained, and sometimes restrained. In STL county, not so much. I have never met a thug cop while OC. I have had only two encounters. One was two minutes and I had the burden to display my endorsement. The second encounter was about 10 minutes cuz I was messing with the newbie cop and had nothing better to do.....he started it and I had his Sgt. end it. He is a good guy and a professional cop.....now.
I have not been disarmed for anyone's safety. Every cop shop around that I know are trained and professional. Though, if you are going west on 70, set your cruise control to 69 and not 0.1 MPH higher.....I'll let other folks fill in the gaps.
Now, for the "political" climate.
I have kept a low profile on the OC front for some time now, because there is not a 2A supporting politician in Jeff City that will not dump their 2A support in a New York minute if bad press pops up because a OCer asserts their rights too much. They are all cowards on that score. If you are contacted by LE as a result of you being armed, make sure you are armed lawful, and make the contact as brief as possible. Do not compromise your principles in the name of expediency. I have the cop call a supervisor. I firmly, yet, politely assert my rights. Reciting RSMo usually gets them to at least give up and leave you alone.
MO is a one party consent state. You and your wife must be able to record your activities, I use a Sony audio recorder, from the time you walk out the front door, until you return home.
My advice? Treat being armed like you treat having two cell phones on your hip. Most folks won't even know, or notice. Be mindful of the property owners wishes and respect their property rights.
OK, I'm done. Ask questions anytime and I am by no means the brightest bulb on the tree. Others will be more than glad to provide that which I may not be able to provide.