So I have kind of a unique situation.

We have a machine network isolated behind a router due to all of the controllers' broadcast traffic.  Our tech would like to be able to test 'new' devices on that network from his desk.  All of the items on that network have manually assigned IPs that have to be on the 192.168.1.0/24 subnet.  Old garbage.

I can create an IP tunnel, but then I am not sure how to route the traffic over that tunnel to ping the other devices not on the local router.  Like I said the IP addresses are manually assigned, so I am not worried about overlap with conflicting IPs.

I am not even sure an IP tunnel is the way to go.  I just need the two routers to pass the 192.168.1.0/24 traffic back and forth almost like they are the same switch.  The switches are both on our company network so there is no need to VPN, unless there is a way to VPN specific ports over to the other router.

Can't you use a VLAN inside the switches to bring the controller network to a single port that you can patch to the desk?
That is how we usually separate all the subnets in our company: use a separate VLAN for each of them, use tagging on
the trunks and configure untagged ports whereever we like.

We could do that, but they like to keep things behind routers anyway.  Regardless I figured out what I needed to do, an EoIP Tunnel instead of just a normal IP Tunnel.  I was doing the wrong one.

how bout trying VPLS perhaps ?

So I have kind of a unique situation.

We have a machine network isolated behind a router due to all of the controllers' broadcast traffic.  Our tech would like to be able to test 'new' devices on that network from his desk.  All of the items on that network have manually assigned IPs that have to be on the 192.168.1.0/24 subnet.  Old garbage.

I can create an IP tunnel, but then I am not sure how to route the traffic over that tunnel to ping the other devices not on the local router.  Like I said the IP addresses are manually assigned, so I am not worried about overlap with conflicting IPs.

I am not even sure an IP tunnel is the way to go.  I just need the two routers to pass the 192.168.1.0/24 traffic back and forth almost like they are the same switch.  The switches are both on our company network so there is no need to VPN, unless there is a way to VPN specific ports over to the other router.

I am facing quite similar problem here. I want to connect two different router in a same subnet. I have 10 pc's. Wondering how to do that.

We could do that, but they like to keep things behind routers anyway.  Regardless I figured out what I needed to do, an EoIP Tunnel instead of just a normal IP Tunnel.  I was doing the wrong one.

Of course it would still be behind routers, but you would bring a port behind the machine network router towards the desk of the engineer.
EoIP can do that too, but you need to be very careful not to wire a short-circuit and cause a loop, or to undo all your hard work separating the networks.

See this link it helped me a lot.
Not neccesarily just for wireless, you could replace wlan1 with another etherX port and skip the wireless settings.