We are providing prebuilt development kits ("devkits") that allow to use appleseed from C++. All features of appleseed are available through the C++ API.
The newer devkits are only available for Visual Studio 2012 on 64-bit Windows.
These devkits rely on a working installation of the Boost libraries. Please follow the instructions contained in this page (section "Installing Boost C++ Libraries") if you need help obtaining and building Boost on Windows. Note that you will need to tweak the headers and libraries search paths in the sample Visual Studio solution to point to your Boost installation.
Don't hesitate to join the appleseed-dev mailing list if you need help setting up or using the devkits.