If you don't want to install the RPM file, and just want to "unpack" it to see what's in the RPM, you have a few options:
1. You can locate and install a program called rpm2tgz which will convert the RPM to a tarball, then you can unpack the tarball to any location and view the files inside.
2. Looking at the manpage, I think that by:
rpm --relocate NEWPATH OR --prefix NEWPATH you can specify where to send the RPM to.
Here's the quote:
For relocateable binary packages, translate all
file paths that start with the installation prefix
in the package relocation hint(s) to NEWPATH.
For relocatable binary packages, translate all file
paths that start with OLDPATH in the package relo_
cation hint(s) to NEWPATH. This option can be used
repeatedly if several OLDPATH's in the package are
to be relocated.