Thank you for contacting us Vicki, we are happy to help you get your blog posts to be full width!
Pavillion uses an earlier version of our theme framework that does not have the ability to fully control the display of the sidebar through the theme Customizer, however there are some adjustments that you can make by using WordPress filters that should help you get your blog posts displaying at the expected size. Our article on How to Disable the Blog Sidebar demonstrates how to use filters to hide the sidebar in our GridOne theme specifically, but the techniques in that article will also work for Pavillion.
Another solution you could try is switching from Pavillion to our latest WordPress theme Crio which does have tools in the Customizer for managing the display of sidebars in addition to a number of other features like custom page headers.
Please let us know if you have any other questions Vicki!