>>Many thanks! The journalling planners link looks particularly useful for me.<<

I'm happy I could help.

>>My progressive neurological illness is just too disruptive, and plans and wishes tend to go up in the air!<<

Alas! That sucks. :(

Alternatives has links for things like fun goals and self-care, including 9 Tips for Setting Intentions When You're Chronically Ill, and some Not To Do lists.

Conversely, awesomeers has Just One Thing posts where you can share what you accomplished today with no advance planning needed.