Hi Sheri,
Sound like you are interested in the mountains in Magic Kingdom.
There are some dips in
Space Mountain but not any large drops or downhills. The drops are not very steep either. The part that makes Space Mountain a little scary is that it is completely in the dark so you don't know when the drops are coming. The ride does start by climbing a big hill like Big Thunder Mountain Railroad but there are no drops that big so don't panic when you start making the climb. The rockets only reach a top speed of 28 mph but it feels much faster because it is in the dark. Because this ride is in the dark, it makes it more of a thrill ride that Big Thunder Mountain Railroad. If you can work up the nerve, Space Mountain is a lot of fun.
If steep drops are not your thing, you may not enjoy
Splash Mountain. There are 3 small dips that lead to the grand drop down 5 stories (52 1/2 feet) of rushing water that will either get you damp or soaking wet. Splash Mountain is located very near Big Thunder Mountain Railroad in Frontierland. You can actually see the big drop from outside the attraction so you can take a look at it before you decide. If you think you can handle the big drop, the 3 small dips will be a piece of cake.
You can find home videos of both rides on YouTube. I have found videos of Space Mountain using a camera that allows you to see the track even though the ride is in the dark.
Wishing you minnie magical memories :-) Allison