Programming software is KPG111D(N), the N version forces narrowband but the non-N version is out there. The latest FW is 5.36 and the latest software is 5.30.
If you have a railroad radio you may want to put new FW in it, since some programming features can't be changed. AAR railroad-specific SW is very hard to get, I've looked and have never found it. Most railroads lock their radios with a password, which requires the engineering key or lab patch to break.
Just look around for KPG111D and you'll find it, or buy it from a dealer.
For cables I recommend Bluemax49ers if you're on a budget and don't want to pay for the genuine Kenwood version. Bluemax includes the software with the cable through a digital download, I think he gives out version 5.21.