We went in late May when Japan had a cold spot right when we expected summer heat. The weather was glorious and we rode a coaster (which I like better than a smaller van or a bigger bus). Our guide Arpun was chill, friendly and responsive to all questions and requests (like a bathroom break soon after we took off from one of the senior tour guests....)
But due to the timing of our visit, we did not see as many flowers. I think best to come early to mid June. So we just explored the shrines and the temples. There were a lot of nice spots for photos. At Hitachi Seaside Park, be ready to do a lot of walking, though you have the option to rent a bike for a small fee.
At the Seafood market, wish we had more time to explore because the nice places had a queue and we weren't quite sure where best to dine. In the end, we went to Minato Bistro, good service and good food.