You will get used to the speed of your scooter soon enough. I am also an avid cyclist (although, I don't do nearly the miles you do; 1200 miles in a year is a good season for me). The thing you'll love about your scooter, is once you get used to the speed, you'll find, in some ways it is much safer, as you are flowing with traffic, and not having cars blast past you with inches to spare as you ride on the very narrow shoulder, or share the lane with them because there is no shoulder.
As a bicyclist, resist the habit to ride in the right third of the lane all the time, and remember what you were taught in the MSF course about using the entire lane, and pick the third of the lane which gives you the best margin of safety, AND makes you the most seen. I usually use the left third, which puts me in the mirror of the driver in front of me, and, also right in front of the driver behind me. It also makes drivers less likely to try to pass on your left in your lane if you are going slower than they want you to go.
Also, don't let the driver behind you pressure you to go faster; esp. if you are already doing the speed limit. As you get more comfortable, and if conditions permit you to do so safely, you'll want to go with the flow of the traffic, which may mean exceeding the speed limit by 5-10 MPH. This helps reduce your exposure to other drivers making unsafe passes.
You already seem to be very safety conscious, so AGATT (all gear, all the time) should already be in your mind. If you're going to do much freeway/highway riding, get yourself a full-faced helmet.
Enjoy your new scoot, and RIDE SAFE!
Jay