Hi Scott,
Thanks for the diagram, in your setup the most important configuration is the managed route in ZeroTier console. So at my.zerotier.com → Settings → Managed Routes you need to add a managed route with destination 10.10.0.0/23 (assuming your security camera network is 10.10.0.0/24) via 192.168.192.2. Note that the destination subnet in the route needs to be slightly larger than the actual subnet (/23 instead of /24) so that clients that are on both networks (like your Server 2008 box) prefer the physical route instead of the ZT one.
At this point you can reconnect ZT on your W10 PC and check that you see the new 10.10.0.0/23 route when you run “route print” on the command line. If you can see the route you should then be able to ping/connect to the Server 2008 box on 10.10.0.100.
If the Server 2008 RRAS box is the default gateway for the security camera network then at this point you might be able to get all the way through to 10.10.0.200, but if not, you might need to add a NAT rule in RRAS:
In this case your “public” IP would be the ZT IP (192.168.192.2) and the private network is the 10.10.0.100 interface.