I'm sorry for your loss. Right now you are still dealing with your mother's death, and your life has been disrupted by caring for her. It may not be the best time to deal with "stuff".
One of the main components of being organized is knowing when to get rid of something that you don't need. Right now it may be hard to dispose of any of your mother's things, because they were hers. I would suggest boxing all her things up and putting them out of the way for the time being. Then organize your crafting area the way you would like it to be, giving yourself room to actually create (rather than just having a place to store all the stuff). Donate or dispose of all the things you already own that you don't need. After that is done, and after you're ready to deal with the possibility of getting rid of some of your mother's things, open her boxes one by one and either place the items in your crafting area or dispose of them. Don't try to do all the boxes at once, or you will be overwhelmed, and don't try to hold on to everything. It's just stuff.