The Lleyn peninsular is a very special place and I have been privileged to spend time there as a very novice camper, later mountaineer, diver and crewing various boats around it. If you have the chance to visit Bardsey Island it is worth a visit, I was fortunate to take small boat over when it was mysteriously privately owned and the locals were very supportive of such private ventures, giving advice on how to beat the tides and other advice. Tudweiliog section of the coast, beautiful mini coves and worth exploring. Porthdinllaen also well worth a visit, pub on the beach with a walk around the headland should be a must.
If there are sea mists, when you are there, then the Yr Eifl may give you some spectacular vistas, to an experience walker the map around this small hill will surely spark off some intriguing routes. There was a deserted village, a ghost settlement of a deserted quarrying company that shipped the stone directly into ships, but I think this has now been developed, but the footpaths seem to have survived to capture some of the history.
There is a walk that the terrain almost demands of a discerning walker, a box route, 3 sides coastal joining across the inland section of the toe that forms the west of Aberdaeron Bay.
The sound between St Tudwal's Islands is a stretch I also favour the beach is quieter there than Abersoch, perhaps not as exciting as the north side, but just find finding a place to look across Hell's Mouth should excite. Especially with 2 areas of open access on either point.
Hope you enjoy your time there, Tracy, plenty of tourist guides but I think your OS maps contain more ingredients for adventure.
PS. A quick look at the Llanbedrog - Nevin service looks ideal for pre-planned linears, provided you use them to outward journey from parking up for return. The Bus route seems to fit in very well with the geography, to my eye anyway.