The {{render}} helper is your friend for this type of layout. You probably want to have the bits that don’t change in your application template, and use an {{outlet}} in that template for the content that will change with the route.
I think overall I’m confused as to the best way of handling multiple models without one route. I guess that’s what Views should cover?
No, a view is an abstraction around a dom element and should primarily be concerned with handling dom events (and turning them into application-level actions).
Your routes should load your data and handle actions. Then they should assign this data or make appropriate property changes to controllers. Controllers present your data to templates (and can be linked together with the “needs” mechanism). Use your routes to set up your data, your controllers to present / wrap your data and connect it together, and templates to render the dom. Use the {{render}} helper to render specific controllers where you need them.