I've been thinking about your request to borrow our van to drive to your summer home for the week. I'd be happy to help you out.
I checked with our insurance agent and she told me I can give you written permission to drive the car, and that our insurance would remain in force as long as we did not charge you a fee for its use. So, we must decline the offer of 25 cents per mile. When you return the car, though, perhaps we could discuss some other arrangement.
I have attached a legal letter suggested by my insurance agent in which you agree to carry your own liability insurance and also to reimburse us for any losses to the vehicle not covered by our own policy.Sincerely