Hey,
If you have a root around under Geometry > Curves > Curve, I think you’ll find lots of useful nodes.
You are already doing a good job of defining your rules, you just need to set them out step by step, and build up the complexity slowly.
e.g.
‘Plus Points are always 1 foot’ node: ‘Point at Segment Length’
‘There are 4 plus points before the first red line’ node: Sequence (start 0, end 4, step 1)
etc. etc.
Have a play and let us know how you get on 
Hope that helps,
Mark