Just install modules as root.

poor man's cpan configuration follows...

If cpan has not been run before, there's a set of questions.
The first I think is if to save (say yes)
Then some questions like
path to ncpftp [] ?
For all those, press enter

You may be asked if you want to set a timeout for interactive bla bla, set it to like 30 or so (seconds).
If you don't set one and you install a module that asks you something before install, it just hangs until you say something.

Then you get to a list of servers, listed
1 servername
2 servername
3 servername
...

Selected two or three, like
12 enter
5 enter
3 enter

then enter again (with nothing as input) to continue

if when we started you selected to save (or something to that extent) you won't ever be asked these questions again when you run cpan

This is all saved to a conf file in ~/.cpan/CPAN/MyConfig.pm or something like that.

So it can be edited by text at any moment (the options you selected).