I've had this setup in my travel kit for years. I use it in every rental car so I can listen to music and charge my phone / use GPS at the same time.

Y-Cable (dock connector to audio & USB): https://www.amazon.com/gp/product/B005LUKCX4

Dock to Lightning adapter: https://www.amazon.com/dp/B014854UWG

For a cleaner solution (and if you also need a cigarette lighter to USB adapter), there's this from Griffin, but it's out of stock and unclear whether it's discontinued: https://www.amazon.com/gp/product/B00NCF0LHC

I've never had anything but a terrible experience with Bluetooth, and I'm definitely never using Bluetooth to connect my phone to a rental car, so I imagine I'll be using the above system for a long time to come.