I'm guessing your Burro has the the 12" overhead cabinets in the galley area. I hung a small microwave
from that cabinet.
I went to Walmart and bought a 700 watt Rival Microwave
for about $55. It was the lightest one I could find. I took the cabinet off which is quite flimsy. I went to the hardware store and got a couple of 1" x the length of the cabinet, strips of metal to bolt to the underside of the top of the cabinet. The bolt ends protruded beyond the lock nuts by 1/2" or so. I used 2 1/4# bolts on the heavy side and 4 #10 screws for the middle and lighter end. I used fender washers in the overhead cabinets. With the cover reinforced it was plenty strong enough to hang. I added a couple of cover screws where I felt they were needed.
I did this a year ago and I have hauled the Scamp
8,000 miles since then and all is well.