I keep getting the message that not all breakpoints are visible and when I use the bar to scroll to the right, it just keeps going and going until it's far off the screen. Is there a way to set it so that it doesn't go past a certain breakpoint? Does that make sense?

Set a max width on your rows

I believe I do have a max width of the rows to 1200 but it seems to not matter.

On the top left of the bar above the slider there are 2 icons (magnifying glass with + & - signs, these are for zoom in and zoom out buttons click the zoom out until the hidden breakpoint appears, be careful though if you delete it ALL the styling below that up until the next lower breakpoint will be lost.