Nav: As stated, most folks use the keypad system. This is just a way to make the position of a known enemy more precise (if you can't see it on radar). Since Main Arena sectors are all 25x25 mile squares, instead of having to search 625 square miles to find the bandit, you can narrow that down to about 64.
Fuel: Again, as mentioned, the E6B is your friend here. The fuel, time, and range remaining for your current throttle/RPM settings are displayed for you. Since we know sectors are 25 miles wide, if your range says 50, you can cover about 2 sectors. That's obviously a one-way trip. If your range says 50 and you need to return to the base you just took off from, you can only go out about half the distance to have enough gas to make it home. This is usually referred to as Combat Radius (how far you can go out to fight and still have enough gas to return home).
A handy tool for navigation/fuel planning is the "Rule of 60". For every 60mph of Ground Speed you have you are traveling 1 mile per minute. (In the Main Arenas there is no wind, so True Airspeed and Ground Speed are the same).
60mph = 1 mile/minute
120mph = 2 miles/minute
180mph = 3 miles/minute
240mph = 4 miles/minute
300mph = 5 miles/minute...etc.
So, if you are flying at 300mph TAS/GS you will cover one sector width in 5 minutes (25 miles at 5 miles/minute).
Experiment with power settings, but keep in mind the Max Range settings are provided for you on the E6B. That will give you the max distance covered for the lowest fuel burn. Also, if you are descending from altitude with idle power, you are burning nearly no gas, so that can save you some fuel here and there.
Be sure to build in a little buffer (extra gas) to get yourself out of combat and headed home.
