MERN is a great starting point. But everybody has certain requirements disqualifying or favoring a project over another one. Here -> http://andrewhfarmer.com/starter-project/ you can find and search through 72 starter projects in case of mern.io satisfy your needs (hard to believe but everything is possible).
I found this the other day. It seems to have really good practices (html streaming and stuff). But I just tried the hello world. Maybe you can take a look a it ;)
Their solution is not easy to implement I guess but it might be one of the best :)
Go for NextJS: github.com/zeit/next.js
Hasnode itself uses NextJS
Sandeep Panda
co-founder, Hashnode
I suggest you check the source code of MERN project. It's a seed project that lets you get started with isomorphic React/Redux apps easily. The read me of the project also explains how SSR is achieved.
Alternatively you can also check this tutorial written by me which utilizes Alt and React to render components on server.