Last time I did an interview about "simple" gas saving driving techniques, I made it simple:
- On the highway: speed kills (your MPG!).
- In the city: the brakes are your enemy. Every time you press that brake pedal, you turn gasoline into brake dust. So drive with the aim of keeping the vehicle moving. (Obviously requires more explanation, and involves several other techniques).
I also brought up using a "game gauge", as you suggested. Also mentioned our 100+ hypermiling tips, that range from simple to OCD-level, for people who want to go online to delve deeper.
Your "extreme" ideas sound fine. The tail is obviously going to be what people focus on / remember.