I read that so quickly, carried along by your ebullience, that I had to go back and read it again to absorb it!
What to do next? I would clear the trash off and start a compost heap. Then sow some green manure, of your choice, for the winter. I find rye particularly good at suppressing annual weeds. With reference to Hugh's comments in wireworm and spuds in 'Edible Plants' perhaps you should decide where you are going to plant potatoes and sow some mustard?
Well established rhubarb will benefit from re-juvenation. Try to see it the petioles are well spaced out. This may be due to the rhizomes having grown out from a central planting over many years exhausting both the soil and the plant.
Will the plum provide a lot of shade? Do you really want it enough to have to deal with the canker?
