Hi @Mjones -
I faced this same problem couple of months back and went through many applications. I found Eagle to be the quickest to learn by far and it has a limited free version.
Another benefit is that it can sync with Fusion 360, allowing you to render a 3D model of your PCB into a 3D model in fusion. Here is a link to something I did as my very first project, learning Rhinoceros 3D and Eagle at the same time - LINK
Also, it runs on MAC 
After this project I invested some time to learn more about Eagle and Fusion. If you plan to do this more often, I would strongly suggest this, there are some very easy to follow Youtube videos. A very good alternative is Altium, but it is way more expensive.
Hope this helps!!
Regards,
Friedl