Here’s the example Router code we ended up with in the 2020-12-15 core meeting:
const DarkLayout = (props) => {
  return <AppLayout {...props} theme="dark" />
}
<Router>
  <Set wrap={[MarketingLayout, HeaderLayout]}>
    <Route path="/home" page={HomePage} />
    <Route path="/pricing" page={PricingPage} />
  </Set>
  <Private unauthenticated="home">
    <Set wrap={[AdminContext, DarkLayout]}>
      <Route path="/admin/users" page={UsersPage} />
      <Route path="/admin/posts" page={PostsPage} />
    </Set>
    <Set wrap={(props) => <AppLayout {...props} theme="light" />}>
      <Route path="/utility" page={UtilityPage} />
    </Set>
  </Private>
  <Route notfound={NotFoundPage} />
</Router>