I think of the most common thing to fail and I go from there. Most common, cables, then adaptors, then PA power.
I carry a plastic toolbox with extra wires, pedals ,adaptors, mic, and extension cords. I also carry a backup powered mixer. Small Carvin XP800. As for the keyboard , no. If that goes and I doubt it ever will, Its just going to be DJ time. I could do some Kareoke with recorded tracks but I'm just not comfortable doing that.
I still have the BK7M sitting around and thinking of selling it. Keeping it for a backup is probably not worth it. But then again at one point I did have 3 G1000's. Thinking it was going to be my forever board. HA!