(Warning, shameless self-promotion ahead.)
Caption. I take many photos each day with the phone, and the problem is remembering why I took a particular picture four years later, and what is the name of that mountain anyway? Caption allows me to easily add text information to the caption property of the photo that does not normally display, but can be read by most photo editor programs and some WordPress plugins.
Some slideshow programs can also display the caption text. I will also refer to the Caption app while inserting photos into my hiking blog each night using the WordPress app.
I wrote the Caption app to help document my photos on long hikes, and I hope it can help you, too.
RecAll. A few years ago I wrote an audio recording program that has enjoyed a certain amount of popularity in certain circles, particularly ham radio operators and telephone call centers, where the voice-activated recording feature was used. Now I have ported RecAll to Android, and will use it to make an audio journal for my next long hike.
A Secret. I wrote another app, useful for taking impromptu photos while hiking, that is not quite ready to release. I am not ready to provide details yet, but if field-testing goes well I can talk about when the trip is complete.