I'd imagine you may have figured this out by now, but there is a fork of PKGI with more features called PKGJ (
https://github.com/blastrock/pkgj ) you should probably check out.
If you haven't yet, extra features (over top of PKGI) include
- queues multiple downloads.
- supports the TSV file format.
- installs game updates, DLCs, PSM, PSP and PSX games.
The VPK is
available here.