Hi Jeff,
Crystal 2011 and 2013 do not come with any SDK included in their installs. Instead you have to download and install the latest Crystal for VS software to work with reports in VS 2010 or VS 2012 and .NET Framework 4.5.
Crystal for VS will work with reports designed in any version of the Crystal Reports design tool from Crystal 9 forward. So, the reports you've created in Crystal 2008, will still work with this version of the runtime components.
See the blog How do you spell confusion; CR for VS, Crystal 2011, BI 4.x and the .NET SDKs.
For download links to SAP Crystal Reports, developer version for Microsoft Visual Studio see this:
SAP Crystal Reports, developer version for Microsoft Visual Studio: Updates & Runtime Downloads
Thanks,
DJ