Cisco Switching/Routing :: Layer 2 Link Configuration VLAN 2626

I've turned up a new layer 2 WAN link between two data centres and i'm having some trouble trying to logically figure out how things should be configured.As you can see from the diagram i've created, I have the link connected on port 13 on one switch and port 14 on the other. Both ports have an IP address assigned to them and they can both ping each other..
 
The problem comes when I need to add routes in order to get traffic flowing over the link.I added an IP address to switch 2 on the link interface (port 14) as: 192.168.4.10
 
I then added an IP address to switch 1 on the link interface (port 13) as:

192.168.1.10
192.168.2.10
 
When I tried to add 192.168.3.10, it said "192.168.3.0 overlaps with VLAN2626". This would be correct as Vlan 2626 has an IP address of 192.168.3.15.

However, if I remove the IP address from vlan 2626 and add 192.168.3.10 to vlan 2 (the link port VLAN), I would surely lose remote access to the switch. (I'm telnetting into the switch from a machine on vlan 2626).
 
I started to tinker with this by manually adding a route to a server in each location and seeing if I could get traffic to flow:

On server 1: route add 192.168.4.0 MASK 255.255.255.0 192.168.1.10 METRIC 1
On server 2: route add 192.168.1.0 MASK 255.255.255.0 192.168.4.10 METRIC 1

If I try to tracert 192.168.1.20 from server 2, the first hop is the default gateway instead of 192.168.4.10.
 
The ultimate goal is to add the static routes to the Layer 3 router/firewall, but before I do that, I need to be sure of what to add to that router (It's a manged firewall from the data centre, so I don't have access to it and I need to raise firewall change requests to get the work done, so want to ensure it's right first time.