Need help modeling data

Hello,

Attached is a a screenshot and active workbook for something I am needing for work.

Basically there is a regular hourly rate, travel rate (half time), and overtime rate (1.5x). Overtime is taxed much higher than regular rates. Travel hours are calculated into your 40 hours first before any other hours.

I am trying to figure out what the ideal about of travel time should be for a certain amount of work for the week.

I can not figure out a way to make lines/data intersect so that you can make comparsions. The only explanation I can form from my data is that the more you travel the less you truly make per hour.

Any tips for the smart people out there?