Is grandma buried locally? Maybe a brief visit to the cemetary and brunch afterwards - as a celebration of life and a re-focus on a celebration to your mom and how much she's done for you. A lovely journal and fancy pen for a gift or one of those daily meditations for moms books
The "firsts" of everything is really hard and awkward after a death. The 1st Thsnksgiving w/o her, your 1st Christmas since her death, etc...Hang in there.