I never really tried desktop upgrade. If you could get it as an OEM upgrade for the OS, ie like a Redhat, or Mandrake or what have you version... It may be O.K.
http://www.kde.org/documentation/faq/install.html
There is the KDE FAQ page. Here is Gnome's
http://www.gnome.org/start/ Personally, considering all to complete this, I'm not so sure I'd care to try. I'm on dialup. Also in an interface like this, tweaking the permissions, and file dependencies, could get tricky, if you couldn't get an OEM install for your version. Mandrake, R.H., SUSE, all seem to be developing and releasing OS versions at a pretty fast clip. If I wanted to stay on the 'bleeding edge' so to speak, I'd try some of the Beta linux versions.
Uninstalling .rpm s using a graphical program like kpackage is right in the kpackage program. The rest of the of the things... Compiling is only needed for source files. Most regular applications, the Binaries are available. Just run the install program. Uninstalling a non rpm file.... This varies. Some programs offer an uninstall or modify script ie Open Office. Some programs only install to 1 directory,
Generally It's not as big a deal to uninstall as it is with an OS that has all kinds of interdependant libraries, and resources
