Hi @YOWGuy,

To fulfill your needs, you need to do two things. The first one is to create a VPN, it can be any type of VPN, it doesn’t matter. Having said that, DigitalOcean has some tutorials on how to configure a VPN. Here is one :

https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-18-04

The next step would be to allow incoming traffic to office resources only from that OpenVPN IP Address. That can be done via your network router. Once you do deny all other Incoming traffic apart from the VPN’s IP address, then you are done.

Regards,
KFSys

Hi,

@YOWGuy wrote
2 - If said employee requests a connection to an office resource (such as a file 
server) they will have access to it without a problem. It is not necessary 
for any of the resources to be auto-discovered (they are all assigned 
via their IP addresses).

I guess the office resources are available just in office LAN with local (private) IP addresses. In that case you need to configure site-to-site VPN between your office and a droplet. Then, employees connected to a droplet would have an access to the office local network.
You could consider an even simpler configuration with single VPN gateway located in the edge of your office network. Employees connected to it would have an access to the company’s internet and LAN.

Besides the tutorial pointed by @KFSys, I recommend OpenVPN community’s ‘how-to’ guide.