want to connect from home to site B
Site A has royal server on publicly facing IP
site B has royal server on non-public IP
there is site-to--site vpn between site A and site B
not all is accessible though this vpn but is through royal server on B
Is there a way to connect to a machine on B through the site A tunnel which in turn will connect through the site B tunnel?
Interesting question. It may be possible when you create a tunnel connection through your first Royal Server using the PuTTY connection type with a specific local port forwarding. You could then configure the local ip/port mapped to your Royal Server B. I've not tested this but I guess this could work. You then need to open the putty connection to establish the first tunnel, once established the other connections using Secure Gateway config should work.