I don't see any security implications of allowing RPC connections, as long as there are no accounts created on that node (by default there aren't). I would then recommend using any of the Ethereum Lite Clients (really depends on your preferred lang or platform) to connect to that node, handling all the encryption (important security stuff) on that local client.

At this point, your biggest problem is running an "open" geth proxy that others could connect to and potentially utilize its resources without your control.

I don't see any security implications of allowing RPC connections, as long as there are no accounts created on that node (by default there aren't). You can then use Web3 to connect to that node, handling all the encryption (important security stuff) on that local client.

At this point, your biggest problem is running an "open" geth proxy that others could connect to and potentially utilize its resources without your control.