Should I use my leased car or rent one for a road trip?

[JJAA]

I want to take a road trip with some friends this summer and I don't know whether to use my leased car or rent one. My lease allows me 12000 miles a year and my car only has 4000 to date. Is it worth the money to rent a car or should I use mine. We're planning on driving a week and a half to California and back to New York.
And I've had the car for only about 6 months now
I am sure that after the trip I will have more than enough miles left as I really only use my car to get to and from school, not much else.