Greeting cards -- they really are a good idea!
I've advised a few posters who wanted/needed to have more contact with distant loved ones, or who wanted to stay in touch but reduce face-to-face contract to consider sending greeting cards. The loved one I was caring for lived with me so I didn't actually do this myself. I based the suggestion on how much he enjoyed getting personal mail.
Now my mother (92, dementia, mobility issues) lives an hour's drive away, with my sister. I am sending her a couple of cards a week. She loves it! My sister displays them on shelves, rotating in new ones after a while. Mom especially likes really corny jokes. I print out cartoons from online and enclose them in the cards that don't have jokes.
But here is the benefit I didn't expect: I'm getting a kick out of picking out the cards! Every time I'm in a store that carries cards I look to see if there is anything appropriate. Many of the jokes she wouldn't get, so I have to read a lot to find one or two ... and spending a little time reading silly jokes is not a bad break from a shopping chore!
I printed a whole sheet of address labels for her, so it is really quick to get a card ready to mail.
Got an elderly loved one you can't (or don't want to) see often? Send cards!