Know who is actually in the house.
Names, days, times, and who to call when someone cannot come. Distance turns a small gap into a whole day with nobody there, so ask how a missed visit is covered before you need the answer.
Decide how you want to hear.
Agree on how you get updates and how often, and ask for the small things in writing: what she ate, how she slept, what changed. No news is not good news when you are three hours away.
Set up the people nearby.
A neighbour with your number. A pharmacy that delivers. A friend from church who visits on Sundays. Write the list down and share it, so help does not depend on you answering your phone.
Use your visits for her, not for chores.
Book the appointments and the repairs into the visit, then leave a day that is just time together. You came to see your mother, not to catch up on her paperwork.
Keep one set of notes.
One shared document with medications, doctors, insurance, the care schedule and passwords. When something happens at 11pm, whoever is closest should not have to guess.