I saw some etrex on the audax, but they are bulky and would just give a breadcrumb trail, no?
That's what you want. Don't use turn by turn on an audax or it will get too clever and re-route you and you will get lost. Believe me, I've tried it.
I use a Garmin 705 which is pretty old but does the job.
I've found turn by turn on garmin 800 works pretty well, though has a habit of stopping working without warning (reloading the track fixes it). What you absolutely want to avoid is having the 'recalculate route' setting on, which guarantees things will go badly wrong.
That's what you want. Don't use turn by turn on an audax or it will get too clever and re-route you and you will get lost. Believe me, I've tried it.
I use a Garmin 705 which is pretty old but does the job.