It can often be much easier if you set the view mode to Outline. Then you can only select objects by clicking on the lines, not the Fill.
As for layers inside layers, you can set ‘Insert inside’, so that new layers you create will automatically be nested inside selected layers. Sub-layers if you like. All of these things can have keyboard shortcuts applied.
I'm confused about why a curve shows to different line widths depending which tool is selected. I am using a custom vector brush, whose width I have set to a 100px. If I switch to the node tool or move tool, the width of the stroke changes to 24px. Why don't all tools display the same width for the same curve? I can imagine this would get confusing when deciding to edit the width of an existing stroke -- not sure whether to edit it in the vector brush properties menu or the context menu for node or move tool...? Why would the same stroke show having different widths, depending on which tool you are in?
Any helpful explanation would be much appreciated, as well as where one should change the width so as not to have problems or for easiest/best workflow.