It is, by far, worth visiting! I remember visiting it when I was younger. I loved it so much so that I had to take my husband there. It was a ways out of the way on our visit, but I knew it would not be a let down. Every time I go anywhere near it I have to make a trip just to see it. Mys husband was also impressed, because he proposed to me there.
There is a lot of information in the museum there about the arch and other things. Although I have never been, you can go up into the arch (one day I will). The view of the Mississippe River from there is amazing, the park is actualy located on the river. In addition, there are several old buildings to look at near there.
Don't think twice just go! You won't regret it!

It has been awhile since I have been in ID, but when we lived there we vsisited the greenbelt often. Most of the time we would enter in Garden City, just past the ball park and Le Bois horse race track. We would go riding as a family and we all enjoyed it.
There are places on the greenbelt that are just belt and trees, there are places where you can get some great views of the river, there is a big fountain off the greenbelt along with s few hotels, restaurants and other shops/vendors.
The greenbelt offers a relaxing and family fun way to be active. I miss it!

Turtle Bay was an ok experience, but I thought it was lacking in some areas. There was a lot of information there for adults or even teens, but there was not a whole lot there to keep my 2 year old impressed. The best part about going to Turtle bay was getting to show my husband (from East coast) a cut Red Wood.
Turtle Bay itself was nothing to rave about, but the Gardens near there are amazing! While visiting Turtle Bay we were able to view the Sundial Bridge as well as the botanical gardens. The plants, trees and monuments within the garden were very intriguing. We spent more time looking at the odd plants and reading about all there was then we spent goign through Turtle Bay. The gardens had a kid area that I thought was amazing! Not to mention our little man loved it!
Turtle Bay also has a kids play area that is rather nice, but it takes more than what I saw to impress me.
I will add that most of what we saw I am used to, because I am from near the area. In addition, we were there in the off season so some things were not up to full potential. I now live near a state Zoo that could make me somewhat partial. Some people love it, but for me I'm not sure I would revisit.

The bridge was quite interesting, but not as great as I thought it would be. The hype was better than the actual Bridge. Most of the hype comes from the extensive amount of money put into the bridge.
I would not suggest anyone make a special trip sepcifically for the birdge. However, if in the area it might be worht the while. There is a great view of Moutn Shasta from the Bridge and there are some other things around the bridge worth looking at. Together it all adds up.

I would suggest that anyone traveling near Burney, CA stop by McArthur Burney Falls State Park. It is located just outside of Burney, CA and is within a decent distance of Mount Shasta and Lassen Volcanic Park. All three are gorgeous sites!
The Park also offers access to Lake Britton. There is a general store, several bathrooms and a very nice camprground located within the park. In addition, there is a trail that runs from the falls lookout to the bottom of the falls and along the river to either Lake Britton or around to above the falls.
At a 129' the falls are not the biggest, but they are still beautiful. I have been several times in my life and they never seem to get any less interesting. The entire view of the Park is gorgeous between the falls, the volcanic rock, the chalk rock, the river, the lake and even the surrounding forrest!