As others have mentioned, the Panda distribution uses KLH10 not simh.
It's supposed to come with a precompiled klh10 executable for Linux and
Intel. It also comes with a pre-installed, ready to boot, system image that
you can use after some minimal configuration, and there's README file that
describes how to boot and configure it. I've got to admit that it's been a
while since I tried it, but I don't remember any problems. What's the issue
you're having?
As for Linux DECnet, I'm afraid this has absolutely no connection. The
Linux DECnet package allows a Linux machine to speak DECnet natively (well,
more or less) so a Linux machine can participate as a node in a DECnet
network. This is independent of any simulations or simulated operating
systems. If you have a lot of DEC machines, it's very handy to be able
access your Linux machines with FAL/NFT, SET HOST, NCP/NML, etc.
Bob