A scooter isn't going to be much less dangerous than a motorcycle...unless you count not being able to get on the freeway with it...
...and while nothing takes the place of your own self awareness of others, at least in Cali, the drivers are more aware of motorcyclists than many other places in the states, like here in Atlanta where if you're not looking then no one else is either...
The trick to finding cheaper insurance on a motorcycle is get to something without any fairings...like a Suzuki SV650 or and older Suzuki GS500... insurance goes down tremendously when the insurance company doesn't have to take into consideration replacing most/all the body work if you have an accident.