Tinstaafl, I'll bow to your greater experience on all the examples you list. Except to point out than none of them is a normal day-to-day task, they are all essential to the flight, and there isn't a simpler way of doing any of them.
TWI: the 10-degree fan line method is very simple. During planning, draw your track on the chart. Then (in a different colour) draw a line starting from the same point, but going off 10 degrees to the left (or right, your choice - or both if you want, but I find that clutters the chart too much).
During flight, scenario 1: you take off, and after 20 miles you fix your position as being half way between your intended track and your 10-degree line. You're 5 degrees off track. Correct by 5 degrees to parallel your track. For the first 20 miles, correct by 10 degrees (instead of 5) to put you back onto your intended track.
Scenario 2: after 20 miles, you fix your position exactly on track. After another 20 miles, you are now off to the left of track. Visualise a line, parallel to fan-line but starting where you fixed your position, then continue as per scenario 1.
The beauty of this is that it is surprisingly accurate, and - once you've fixed your position - requires no attention to be diverted away from other tasks except for a very brief glance at the chart.