Taking the Caines Head Trail from the Lowell Point parking area to Tonsina Creek is about a 3.5-mile round-trip hike, which takes our family (kids ages 3 and 5) between 2 and 3 hours to complete. We tried this hike on the suggestion of another family with young children and are so glad we did!
The trail begins at the upper Lowell Point day-use parking area, which includes pit toilets and some nice maps. We always snap a photo or two of maps at a trailhead with our digital camera in case we need to reference them while hiking. The first part of the trail follows a wide gravel road along the top of a bluff before turning up into the forest and narrowing a bit right by a picturesque waterfall. There were many spots along the trail that were muddy and even had streams flowing right across the trail, as we were hiking on the first dry day after several days of rain. Be sure to wear waterproof hiking shoes and clothing that you don't mind getting muddy!
There were only a few ups and downs, making it easy to walk even for our 3-year-old. The very last portion leading down to Tonsina Creek is a series of switchbacks descending the bluff. That portion may require hand-holding for safety but affords spectacular views of the bay and mountains. At the creek, there is a bridge from which you can view spawning salmon in the summer months. Also be on the lookout for bears that have come to have a salmon lunch. Keeping up your noise level is a good way to scare off bears, and it's easy to do with kids along--just sing or talk loudly.
You can continue on the trail for as long as you like, but we chose to turn around at the first bridge since we had to go back up the bluff to get back. If you plan to go further, be sure to check on the condition of the next bridge at the beginning of the trail. It was washed out when we went in August 2011.