welcome to KS. I advise going to http://www.handgunlaw.us to find the most up to date information on gun laws anywhere. just click on KS and the laws will pop up in pdf format.
Open carry is legal almost anywhere but I recommend still getting a concealed carry permit. the class has great information that will help you in your transition back to the states.
Permits are great for crossing state lines and gives you more options like carry in school zones of the state you live in. on the site you can create a map of what states accept KS permit.
Have great 2015