It won’t help you on client side, it’s the VPN server that must know where 10.15.2.0/24 subnet is. And currently doesn’t. So you must find a way how to add this route on VPN server. Or if you’d in fact need to access only some service in 10.15.2.0/24 network (and not the whole network), you could do it using port forwarding. In other words, devices from 1st LAN would be connecting to IP address of VPN client (192.168.27.66) and you’d forward port(s) from there to 10.15.2.x.
And that adress you don’t know, downloading /mikrotik.php and enabled SOCKS proxy, I’m affraid I have some bad news for you, it looks like hacked router, see Winbox vulnerability: please upgrade. Not very surprising, since you have no firewall (you have some rules, but they allow absolutely everything).