What a wonderful project for your guild to undertake. Don't know about pens to write with, but one word of caution donating to nursing homes.
I have seen/heard a lot of sad stories about quilts given to nursing homes being misplaced, 'lost', found in someone elses' room WITHOUT a label. If it is for a specific person, you might want to attach the label in a way that is NOT EASY to remove, or write it directly onto the backing fabric. Some of the stories have been from relative of patients who gave lap quilts & they 'disappeared' - till a search was made & they were found in another's room w/no label.
Have a blessed Sunday & happy quilting.