This isn't possible out of the box, and there aren't currently any adapters available from TLG to support this as far as I know. I did come up with a modification to make this possible, though.
My goal was to allow me to modify the hub to receive external power in a way that did not damage the hub and would be totally reversible. Ideally, I wanted a solution ...
Since June 2019, this is possible. See here:
Look right at the bottom of the article.
The latest version of the Powered Up app (2.2.0) as well as the latest
version of the Boost app include new firmware for the Boost hub. After
this update it is possible to ...
If you prefer C#, there a new lib on the block: SharpBrick.PoweredUp. While the Boost hub and motors are missing, the protocol is implemented. Your use case should be two minor contributions away.
Full Disclaimer: I maintain the library. I do not have Boost Hardware but the protocol officially supports Boost Hub. Just some enums and types are missing.
It depends on which app you want to use. My impression is that the Boost app can work with one Boost hub, one Boost motor and one Boost color/distance sensor.
If you use the PoweredUp app, you can use WeDo sensors and WeDo motors as well. But you always have to set the ports explicitely and remember that the external ports on the Boost hub are ports C and D. ...