I would recommend using an appstate Map or a page level component that holds the state for the features of your toolbar. If using an appstate, you could use can.route.map to bind certain features of the appstate Map to the route, so the state of your app can be controlled by the URL. A page
attribute, for example, would control which main page is displayed (say, the message list or the contacts list.) You could then listen for certain values of page in your stache template to switch to showing the correct page. This snippet would show the message-list whenever the page attribute of the appstate is 'messages': {{#is appstate.page 'messages}}<message-list></message-list>{{/is}}
If you had more specifics of which feature is hardest to figure out how to implement, I might be able to give more specific advice.