There's also otto, a JavaScript interpreter written in Go:

https://github.com/robertkrimen/otto

Here's an example Go app using otto for React server-side rendering:

https://github.com/101loops/go-reactjs

Its great but still too slow for that.

Sounds like you're looking for Rendr.

No need for Rendr if you're using React -- React is easy to server-side render on its own (assuming you're already using node on the server).

Not everyone wants to use Node...

Why not use a node script for this one part? Seems to me pretty wise to use a javascript runtime when evaluating javascript. You can still use Go or whatever else for all your other tasks.

Just simplicity of the deployment. Now I think the right solution is an RPC to a NodeJS server, like you said.