I have only ever used the installed version, so I don't know what the portable version might need. The installed version wont give you previews etc. without the extensions being installed.
The extensions were once available separately, but now they are in the new version downloads. ( Don't know if they are in the "portable" downloads).
Just by the way, I tried a lot of different programs/option to get this functionality, and PDF-XCHANGE is the only one that works consistently and well.
If you have a large number of PDF files in a directory, it may take a moment for the icons/previews all to be loaded. In a directory with about 700 PDF books it takes several seconds to load them all on my machine. This is not really a problem.
Finally, the preview pane in explorer will give you the functionality of the PDF-XCHANGE controls shown, with one small exception/bug. You can not enter a page number to jump to automatically. All the other controls shown work as expected.
More information; http://www.tracker-software.com/shell_ext.html