Nice work, especially so fast. Don't forget that sunlight can deteriorate Great Stuff if it is not thoroughly painted. I couldn't tell for sure if the Great Stuff on your prop was covered.Sorry no pics but it is simple. Round cardboard base, chicken wire type material as a base with foam blocks underneath for support to give it some height. About 250 red and orange LED string lights on top of the wire. Laid sticks on that wire and put a modest layer of Great Stuff on and around that.
Finally used black, chalky grey and red spray paint (not too much) for some character during the day time. Grey actually really help make some of the exposed wood look ashy.
Finally, I may copy another haunter here, forgot the name, and spray a but of black rubber coating on this and cover that with real ash... haven't done that yet.