You'll have to judge when you get there, I think. My DD, 4, just hit the 40 inch mark when we went in December. All she talked about before we went was how much she wanted to go on Splash Mountain and Thunder Mountain. She had seen the MK DVD. Well, we took her on Soarin in Epcot...a very gentle ride...but she hated it. Then we took her on Test Track, and she really hated that. After those, she was scared to go on any rides...she thought they all would be dark, high or fast. She said BTM and SM were definitely out. DS 6 didn't like BTM either. He was very happy when it broke down towards the end of the ride and he was able to get off.
So my advice would be to do the gentler rides first...Small World, Pooh, Peter Pan (all appropriate for your one year-old as well...we took my DS when he was that age and he had no problem with any of the gentler rides...if he wasn't entertained, he just fell asleep!). As a roller coaster warm-up, you could try Goofy's Barnstormer in ToonTown. Dumbo might also be a good test because if your child is afraid of heights, or the up and down sensation, that ride, while gentle, will bring that out.
We had a really hard time with DD after taking her on some of the rides she didn't like, and I don't want you to have the same experience.
Good luck!