We feature our Peerboard subdomain as a first-class member of our main domain's site navigation and redisplay the main domain navigation as the top navigation in Peerboard. It would be good to have control over whether links open in a new window or not so that users to not accumulate browser tabs and become disoriented.
E.g. https://wormpeople.com/ (main site) and https://discuss.wormpeople.com/ (peerboard)