This is such a hard time, went through it two years ago. We gave away to her friends
what was worth giving and got a clearance firm through the council to take the rest. We were clearing in London and the big prob with trying to get stuff to charities was transport, we didn't have any and neither did the charities.
Part of the grieving process is anger which doesn't help. We were going crazy trying to treasure every little thing that she had left and put it to good use (My Dad died some years ago) In the end we decided that we were allowed to take the easy way out. The firm we used to clear was very good and didn't charge an arm and a leg. there wasn't anything worth selling that they needed to take and it happened quickly which was a blessing.
I am sorry for your loss, I really know how hard it is.