I have just released beta-2 of WordPress Google Form v0,58. This update addresses a couple of significant issues, notably the inability to disable some of the default options.
The problem with the default settings based on checkboxes is described pretty well in this article by Devin Price. I was dealing with the essentially the same problem Devin describes although my solution is slightly different, his solution was helpful in fixing this problem.
While fixing this problem I also added a new Reset button which appears on the Advanced tab. This Reset button will reset the plugin to use the default settings.
This beta release also includes a fix to address the problem when an ampersand appears in a text box on a multi-page form. This problem was reported on WordPress Support Forum.Google Forms Beta (1011 downloads)