Thank you @RomanZ! That pointed me in the right direction to get it working.
For anyone else looking at this, here is what I did:
Disclaimer - I'm not a linux expert, so use at your own risk.
1. Removed /etc/init.d/btsync to prevent auto-start
2. Created .btsync folder in user home folder
3. Created storage_path folder in .btsync folder
4. Copied /etc/btsync/user_config.json and /var/run/btsync/btsync.pid to .btsync folder
5. Edited user_config.json as follows:
{
"listening_port" : 0,
"storage_path" : "/home/USER/.btsync/storage_path/",
"pid_file" : "/home/USER/.btsync/btsync.pid",
"agree_to_EULA": "yes",
"webui" :
{
"listen" : "127.0.0.1:8888"
}
}
6. Created a crontab entry to run a script that launches btsync using the newly created user_config.json file at boot. You could skip the script and just put the following entry into the USER's crontab to start on boot:
@reboot bash /usr/bin/btsync --config /home/USER/.btsync/user_config.json
7. Finally, I removed the BTSync PPA from Settings > Software & Updates > Other Software so I can control any changes in the future.
Enjoy!