Can you climb stairs? If so, you shouldn't have trouble on many rides.
Are you asking about ALL the rides or just specific ones? I doubt you will find exact measurements but I can guesstimate for you based on my extensive number if trips to
Disneyland as a local.
Coasters: you step down into most of these. Thunder Mountain is the closest to just walking in. It requires a very small step down. Space Mountain and Incredicoaster require climbing down about 12" and then climbing back out. Matterhorn is VERY difficult to get in and out of. Goofy's Sky School is tricky as well, as the car doesn't stop and it's a tight squeeze to get situated with the T shaped lapbar. I'd recommend skipping that one.
The omnimovers require something like a 4-6" step up. These should be no problem. They can be stopped if you need extra time. The boat rides are all pretty easy. You step down into them, but you can easily step first onto the bench and then down to the floor. Distance from ground to bench seat is a few inches, then maybe 10" from bench to floor of boat. There are handrails you can hold onto as you get in/out. Cast members will offer you a hand on the Jungle Cruise.
You have to climb stairs into the train. It's like climbing a staircase. There are 2 steps.
Indiana Jones requires climbing up into a Jeep. If you can get into an SUV, you can do this. It's not a big step up.
Some rides you just walk into: Soarin, Star Tours, Millennium Falcon Smugglers Run, Guardians of the Galaxy (front row), Pixar Pal A Round, Mark Twain Riverboat, Silly Symphony Swings, Tiki Room