No Perm Address For a Few Months. What to do?

My best friend is moving from OH to CO later this year. She'll be moving at the end of a lease and will be staying in a furnished rental for 3 months or so while she finds a new place to buy.
What can she do about auto insurance in the meantime? She can't use the rental address as a perm. address and won't have one anymore in OH so what does she do for an address while in this transition? A PO Box won't be accepted, will it?
Is she supposed to pretend she's going on vacation and just hold onto her Renter's and Auto policy until she has a new address even though her lease is ending? She'll have some stuff in storage that's covered by her Renter policy so she wanted to hang onto that, too, but she can't do that without a real address either, right?
If she uses a friend's address in OH, how does she prove she lives there, especially since she won't be living there?
Can she just give her insurance company the OH friend's address as her new address and tell them she's going to be on a long vacation or work assignment in CO and give the rental address for the garaging address so her car is covered?
She's not trying to commit fraud or anything, but what are the options for people while they're in limbo like she's going to be?
Is she supposed to keep paying a lease in OH just so she has an address? That seems crazy.
She googled it and came up with no good answers for her situation, she said, so I told her I'd ask here since she doesn't want to alert her insurance company in case they drop her or something over this.
Thanks for reading and for any help on this!