is it possible to have lap times not overwrite course view in the display - i.e. have only audio prompts of laps during a run and no visual representation on the watch? That should help me not miss turns for preset courses..

I don't think so, but perhaps someone else will prove me wrong. On my watch, the summary only displays for a few seconds and is gone, or I can dismiss it immediately with a press of Up or Down. You could also turn Auto Lap off and manually lap when you want to see a summary.