so here it is... a bit later than expected..
This assumes you have a fresh installation of Ubuntu... (I specifically have Ubuntu 16.04 Server working with this in a VM under FreeNAS) ..SSH into your Ubuntu installation and enter the below;
sudo apt-get upgrade
sudo apt-get update
sudo apt install curl -y
sudo curl -sSL https://get.docker.com/ | sh
sudo docker run --restart=always -d --name lancache -v /srv/lancache/data:/data/cache -p 80:80 steamcache/monolithic:latest
sudo docker run --restart=always --name steamcache-dns --detach -p 53:53/udp -e USE_GENERIC_CACHE=true -e LANCACHE_IP=$HOST_IP steamcache/steamcache-dns:latest
sudo docker run --restart=always --name sniproxy --detach -p 443:443 steamcache/sniproxy:latest
sudo docker exec -it lancache tail -f /data/logs/access.log
The last line of code above gives you the log file which will list the files being downloaded / cached.
Yes i successfully got this running, however I didn't follow the guide on the site but something in between the guide here and what the site says.... I might write something up here later if I have some time this weekend.
Those of you looking to set this up might find this a bit easier / better, especially if you're looking for more than just Steam (this includes Windows Update);
https://hub.docker.com/r/steamcache/monolithic