Hi Keith,
We did a 'sampler' tour through the PacWest this past summer (latter half of July). You could easily spend two weeks in the area. Our hiking-focused trip encompassed 1200 miles through Washington and Oregon (North Cascades, Mt. Rainier, Mt. St. Helens, Columbia River Gorge, Pacific coastline, and Olympic). The routine was hike/drive/sleep/repeat. Normally, these trips are photo-intensive. Not this time.
For our brief visit of the Olympic area, we drove North on US101 from Cannon Beach, Oregon (site of Haystack Rock), stopping at a couple of the coast sites and the Hoh rainforest along the way. Our next overnight stop was in Port Angeles - the gateway to Hurricane Ridge. As an added bonus, we were able to hit some tide pools just outside of Port Angeles (Tongue Point in Salt Creek St. Park).
Of the beaches you listed, ShiShi and Point of the Arches is the toughest to get to. Not so much tough, but the long way around. Rialto, Ruby, Second, etc. are short "parking lot" hikes. It's important to do your research on the tide charts. For example, at Rialto, we thought that we had enough time to make the mile trek to Hole in the Wall; however, the tide came up too fast to make it 'through' the hole. No matter which ones you visit, they are awe inspiring.
The Hurricane Ridge area should still have plenty of snow in early May (snow chains are required in the vehicle through May 1).
Pick up a copies of:
Day Hike! Olympic Peninsula The Photographer's Guide to the Puget Sound & Northwest Washington
You might also be able to pick up some pointers from folks on the
NWHikers forum. Their forum has trail and location info. Plus, there is a sub-forum for photography
Have a great time!