You can do what most writer types do. Here, there, anywhere, wherever. Some way to keep track of miscellaneous info you pick up on your travels. Your needs supplied, below. I strongly recommend going there as a first lesson.
Doc files are the large, Palm-readable, text files.
It's a special Palm format, not related to MS Word' s .doc. This Is Good. Then you must get a keyboard. Writing on the little handwriting-recognizing screen is incredibly difficult for long blocks of text. For the rest, you have it all built in.