Ask HN: Small startup networking setup

Please forgive any potential naivety/conceptual misunderstandings, networking is not my forte but I am needing to put my sys admin hat on to design a network for my startup.

Haven't found a lot of useful information in various available guides as my requirements are not typical.

The primary purpose for the time being is to allow easy access to our deep learning workstation from anywhere without worrying about port-forwarding or issues caused the ISP router's ip changing, and to avoid worrying about crazy NAT workarounds required for applications such as mosh. The VPN is not assumed to be secure by the devices on it, although the extra security provided is a plus.

I believe I understand how to set up openVPN directly into the workstation, but it seems desirable for the VPN to tunnel out of a dedicated router to allow for easy future expansion.

Pictorially, I desire a set up like this:

[internet] - [ISP modem/router] - [VPN router] - [workstation]

where any devices connected to the VPN router can talk to each other and are accessible over VPN.

Is my understanding correct that I can accomplish this by getting a DD-WRT supporting router and hosting openVPN on it?

Thanks in advance for your help, Andrew