Yes, I concur with talexb that option 2 is the way to go.

Start a project directory and make subdirs:

lib/
t/
bin/
[download]

Put your modules in lib/ using a top-level dir for the top level part of your namespace (if you one day distribute to CPAN you will want a distro name under PostScript and not put your modules directly under the top level) and maybe using subdirs for segments of your desired namespace:

/lib/YOUR_DISTRO_NAME/PSjoin.pm
/lib/YOUR_DISTRO_NAME/PS2png.pm
/lib/YOUR_DISTRO_NAME/PStopdf.pm
/lib/YOUR_DISTRO_NAME/Utils/Frobnicate.pm
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and use them like

use YOUR_DISTRO_NAME::PSjoin;
use YOUR_DISTRO_NAME::Utils::Frobnicate;
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Add that whole directory tree to a version control system like git. Do it first! Then write tests in t/ for all the things. Maybe use subdirs there for the different modules, maybe it's by functionality, maybe both: that's up to you.

Then when you want to build a distribution in the future your files will be in the proper structure. You don't have to worry about such packaging tools now, but preparing for them is wise.

Hope this helps!