The joys of Bluetooth becoming so much more accessible nowadays... I'm going down a similar route now that my buddy box is up and running with the integrated HU, amp, sub and component speakers. I'm looking at using a Bluetooth receiver (as per link below) and a 12v to 5v DC board so that I can take a power source straight from the amp power cables to the Bluetooth device. I'm trying to keep everything within the confines of the buddy box, so that the only thing plugged into it is the Vibe plug for the power and remote switch on. Ok, so I'm still running a HU, but in theory the BT device should also plug straight into an amp if you so wished. I will post up some pics on my thread once it has arrived and I can have a dabble in the garage for a few hours.
Looking forward to be able to control the music in the van from the comfort of the camp fire!
https://www.amazon.co.uk/Logitech-Bluetooth-Receiver-Audio-Adapter/dp/B00IJYG4FY/ref=sr_1_2?ie=UTF8&qid=1540830757&sr=8-2&keywords=logitech+bluetooth+audio+adapter