• ssh to remote, forwarding some remote port to your local ssh port (-R)
• ssh from remote through the exposed port, starting socks proxy in the process (-D)
• use socks proxy explicitly or find some tool that can route the traffic into it

Similar approach can be used to establish VPN tunnel with no encryption (ssh already provides that), routing everything but your ssh connection through it.

• ssh to remote, reverse forwarding your VPN-over-tcp server’s listening port
• establish vpn connection on remote, route everything but your ssh connection through the newly established interface

It will be wasteful, but it will work.

Gl.iNet is a great value router, but if you want to do anything really interesting, it won’t do.

I have Slate AX chugging along, and have been eyeing teklager boxes to do actual routing, with slate as an access point.