the machine in your network running as media server should have local access to the principal library. For best results it should be on the system drive. The media files themselves can be anywhere.
So either your fanless PC is the "server" or it is a client. If it is a remote client then the other machine should be the one to run media server at startup. If you want it to be the server machine, install the library on its ssd (you could backup the file from machine 2 and restore it to the fanless one). If you do the latter it has to be on or allow wake-on-lan to get it running. JRemote can do the waking up directly btw.
If the "other" machine is a NAS, generally this won't work -- although recently JRiver can be run on some QNAP NASes (have to search on the forum for this).
JRemote would work in both cases. I found it easier though to use the PC I want to control via JRemote to run the server program and have the main library in that one running locally. Most admin can be done from the client, and the few things you can't do you can use Teamviewer or VNC occasionally.
hope this helps some