This kind of extract-and-go package is exactly one of the goals of FIRSTclipse. They are currently at
http://www.astro73.com/download/eclipse/. You will want
eclipse-full-3.2.1.zip, which includes Eclipse, CDT, subclipse, the toolchain plugin, and the error parser plugin. This file is for Windows only.
In addition to the compiler (MCC18), you need one thing: GNU Make. You can use either the Cygwin version or the native version. I will post the native version to my website when I can get through on SSH.
I've found that some of the values have to be handled oddly in the makefiles, as well as the error parser lacking a name. Both of these will be fixed in a future version.