To my mind, README serves 2 purposes. One is a high-level overview of the dist. With this in mind I will usually include in a README: the current version and release date, a brief description of what the dist does, a list of changes since the last release and the licence and copyright details.
The other purpose is to tell people new to Perl what to do with the tarball they have just unpacked. So that means including the stuff that Module::Starter has put there already about perl Makefile.PL, etc. and then how to find the more extensive documentation (the POD) which will explain how to use it.