Is it good for a short day trip with only about 5-8 hours of time to explore?

Yes

Perfect, really.

Yes absolutely, my family does this frequently. If you can time your stay around low tide you can spend a good portion of time exploring tide pools. Harris Beach and the surrounding area is great for day trips...

Plenty of time to hike the trail and the beach.

Absolutely!!! Its perfect for a day trip. Make sure to go to the far ends of both sides of the beach to see some pretty amazing hidden gems. Have fun

Totally!