@katzm5 ...
I'm pretty sure that you can do this with the Design Tools (DesignPLUS) product from Cidi Labs, but there is a cost to that product. I'm not as sure, however, if you can do that using iframe HTML code, though.
HTML Iframes (w3schools.com)
When I tried to apply similar code to a page in my sandbox course, I ended up with a page looking like this:

As you can see, duplicated global and course navigation buttons appeared on my page...which were all clickable...but that's not what I would want students to see. I wonder if what you had seen was something that was using Design Tools? Maybe there are other ways to do this (without Design Tools) that I'm not aware of, but the ifame way I tried wasn't successful.
I'd also be concerned about page length with the way you want to have things set up...especially for your students who are using mobile devices. At a Canvas conference several years ago, I once heard something that has stuck with me..."you may not be using mobile, but your students are". So, when designing your course pages, keep in mind the amount of scrolling that your students might have to do on a phone or table using the Canvas Student app...compared to using a laptop or desktop computer.
I hope this will be of some help to you.