Building and running new package versions not yet in pkgsrc?

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

What do I do if I want to build and run a package where pkgsrc version is not 
up-to-date, and I want to build and run the current release version of that 
package, like Abiword 2.8.6 for instance, when pkgsrc version is far behind?  
Or maybe I want to try a new alpha or beta development release of a package 
like Firefox or Seamonkey, but don't want to burn my bridges on the already 
installed and running version.

Can I create a testing install base such as /extra or /usr/extra, and set 
something like
PATH=/usr/extra/bin:$PATH
and perhaps modify some other environment variables, and then be able to return 
to the regular environment?  I would only want to change a few things 
temporarily and would not want to create an entire chroot system.   


Tom