I've got a rider policy under a truck that has full coverage through Farmers Insurance. It is a limitted use policy but my agent said I could drive as much as I want as long as it wasn't my primary vehicle. It set the value if it's totalled and they set the premium accordingly. A un/underinsured and liability policy is included. Since I drive them less than 2000 miles per year, this policy works great for me, especially at $20.00 each every 6 months. That's less than 1 tank of gas for one of them and I've got three covered this way. See if your agent can come up with something like that,
Good luck,
Scott