It very much depends what you want to do. For occasional, very minor edits I've found sejda.com useful. Runs online so no need to install anything, but the free version puts very stringent limits on how many changes you can make.
Lorraine McCall began her attempt today at a continuous, self-powered round of the Grahams, a four-month tour of upland Scotland combining walking and bikepacking. If successful, she'll be the first person that we know of to do it.