We hiked this trail pretty often when we lived in Hawaii. It's a great trail to take the dogs on when you want a change of scenery from the beach but still want somewhere they can swim and cool off. This trail is usually extremely muddy, so wear shoes that you don't mind getting mid all over. There is also one small section of the trail that is very steep hiking out (Cardiac Hill); otherwise, it is a very moderate trail - slightly challenging but not exhausting. There are a couple of turns that aren't extremely well marked, so it's also a good idea to take a trail map your first time. But there are also usually a lot of people on this trail, so you can ask someone which way to go if you are unsure. At the bottom there is a pool with small waterfall and Creek so many people hang out there.
If hiking in Hawaii with dogs, make sure that you get a lepto vaccine. It's a big problem in Hawaii, and I say better safe than sorry since it's pretty hard to keep your dogs from drinking water.