Although you can cover the Ring in one day by car or three days by bicycle, the more time you take, the more you'll enjoy it.
The road is narrow and twisty in places, notably between Killarney and Moll's Gap. Tour buses travel the Ring in an anticlockwise direction. Getting stuck behind one is tedious, so consider driving clockwise; just watch out on blind corners.
From late June to late August, Bus Éireann (www.buseireann.ie) runs a once-daily Ring of Kerry loop service (No 280). Buses leave Killarney at 11.30am (Tralee at 10.50am), arriving back at Killarney at 4.45pm (Tralee 5.35pm). En route, stops include Killorglin (€8, 30 minutes), Cahersiveen (€16, 1½ hours), Waterville (€18, 1¾ hours) and Caherdaniel (€21, 2¼ hours).
Year-round, Bus Éireann service 279A runs daily between Killarney and Waterville (€18, 1¾ hours), via Killorglin (€8, 30 minutes) and Cahersiveen (€16, 1½ hours).
LocalLink Kerry minibuses run between Killorglin and Waterville (€8, 1½ hours) via Cahersiveen (€6, one hour), three to four times daily (once on Sunday), with one or two continuing to Caherdaniel (€10, two hours).