Wouldn't say I am smarter bigredfish, but just went through a similar exercise.
Can't really tell from your screen shots above, but the main router and secondary router should be different ip addresses. The main router should handle DHCP. The secondary router should have DHCP disabled.
You indicated " router in garage and NVR are both on 192.168.1 and internet coming from house router is 192.168.0."
One of these routers (probably house router with 192.168.0.x) should be left alone.
The other router should be changed to have an address to match the house router, plus 1. For example, if house router is 192.168.0.1, then the other router should be 192.168.0.2, with DHCP disabled.
Note: The gateway address of secondary router will need to point to the ip address of house router (ie., 192.168.0.1)
Is NVR getting it's ip address from DHCP, or is it static? If static, you will need to change the gateway of NVR to match the ip address of whichever router you plug it into.
IP addressing on the NVR and other router should be changed to the same subnet of house router, assuming that is what you want to do. This will probably be easier than setting up a separate network, but depends on your objective.
There is probably something I am missing on the setup of the secondary, it's been a while since I set mine up, but if you google search how to setup 2 routers, you will find plenty of info.
