[mrlmd1]

65 for most of these bikes is a good cruising speed, 70 may be pushing it a little if you expect to maintain that speed and it all depends on your weight, wind, etc.
65 in 4th gear is over-revving the engine and should be used for maintaining speed up an incline if you need it, not for long term riding at that speed. The bike has just so much horsepower and you don't get any extra over-revving the engine, just more wear and tear on it.
Some people use the kill switch to turn off the engine, others use the key - your choice. Just make sure it's in the Run position if you want to start the bike.,