the shuffle plays songs in the order you put them in when you load them onto the player. it does have a *shuffle* mode that randomizes the play order. there are NEXT and PREV buttons so one can skip over songs or go back to previous songs. fyi
alas, the shuffle is only 1 gb (1000 mb) so it won't suite your purposes. i love the 1st generation shuffle. it's the size of a stick of gum and virtually indestructable. has better sound quality compared to any of the nanos, past or present. some speculate the current generation of the shuffle is made with even poorer quality components, thus degrading the sound quality. generally, apple uses the cheapest quality components to make their ipods, but has shiny and slick packaging and great advertising to make up for their inferior products. [/end editorial]
generally, you can compress a given mp3 file down to a smaller size. a typical audiobook-type recording of an hour long will be 50-200 mb. just figure out roughly how much total storage you might need, and get a player with that much or more. there are some players that have a memory slot, so you can just buy a new card and plug it in when you need (just like a digital camera). for hiking, i would advise against getting a hard-drive based player. generally, flash-based players tend to survive rougher handling much better. fyi