we took dd on matterhorn when she was tall enough for at 2 years 9 months old. she loved it! she kept asking to go back on it, 4 times in a row! good thing we were there when it was slow, lol.
splash mountain might be okay, the drop at the end is really more thrilling than scary, and it's over quickly. everything inside is fun. you can hold onto him if you sit all the way in the back of the log with him.
BTMRR is one that my kids all love. my youngest went on it for the first time just this past september when he was 3.5, and loved every second.
the only one i, personally, am a little leery of with really little kids, is space mountain. it's not just that it's so dark through the entire ride, but that's a big part of it. however, the way the bars come down, it doesn't really feel secure to me, for really small children. we took my daughter on it in '07 when she was finally tall enough (at age 6), and i held onto her tightly through the whole ride because it just looked like there was enough room for her to slide through the safety bars. my youngest was tall enough for it on our last trip this past september, but both DH and i just didn't feel good about putting him on it. we'll go back in august, and will let him ride then, but i'll hold onto him tightly the whole time, too. the dark won't bother him, but he'll be nearly 5 years old by then. if your little guy doesn't like the dark, i would think skipping space would be your best bet.
hope your family has a great time!
