I assume that the insurance is also paid for by the company who's paying the lease?

If so - they typically dictate who is allowed to drive the vehicle (At least, with my father's company vehicles he's had they do this - they would only allow a spouse, not kids).

If you get into an accident, there is the potential that the insurance company will not cover the damages, especially in a place like Cali. where insurance fraud/injury settlements are much larger than Canada...

Either way talk to the people who insure the car - they're the ones that you want to get the OK from. Especially being from out of town and sight-seeing, you have a better chance of getting into an accident as you would normally...