Set Up My Own VPN

NOT for bypassing censorship, etc.
Setting up a VPN. During my work, there are often times I need remote access to my computers behind firewalls and/or routers. I used to enjoy LogMeIn Hamachi (HMC), but that app (1) appears to have died and (2) does not support latest macOS releases. For these two reasons, I'm switching to ZeroTier One (0T1). 0T1 allows for up to 100 connected devices per network, which is a huge plus compared to the 5-device limit on HMC.
Just remember to toggle the checkbox under "Auth?" column in the network configuration page at Wasted one minute on this.
Graphic control. It's never wise to rely on one type of network and call it for a day -- SSHing into another machine can be blocked by a public Wi-Fi network, and I've been there. Besides 0T1, I also set up a RealVNC network for 5 of my most frequently connected machines. Why 5, you ask? That's the limit for a free-tier network from RealVNC.
Transferring files. Transferring files shall better be achieved via rsync rather than relying on scp, which I enjoyed using for a couple of years. I've always heard of the powerful mightiness of rsync, but it's not until recently that I need to move thousands of ~1MB files from Philadelphia to China (legally; it's important to point this out considering recent China-USA political trends) that I discovered its ability to increase the performance by ten folds.
Terminal session persistence. I set up an alias for the following command:
ssh -tY [email protected] -i ~/.ssh/KEYFILE_rsa 'tmux a -t MyServer || tmux new -s MyServer'
where tmux a -t MyServer || tmux new -s MyServer essentially attempts to attach to a tmux session called "MyServer", and if it fails, a session of that name is created & attached.
In this way, I can restore my last terminal session with one command. Handy!