Out of the adult rides at Disneyland I would avoid Space Mountain and Indiana Jones. not sure about Matterhorn because we never went on the new sleds. When in doubt, try to lift up your stomach over turnstiles, lap bars, car openings, etc.
I always over think these kinds of things, yet it always ends up being a good day and very fun. Everyone is very nice at Disneyland, no one will make a big deal about it. My best strategy to share is to just walk up to the attraction and check it out; look at the seating as best you can and see if there's turnstiles or an alternate entry. Just go and have fun