My parents are in there 70’s and heading to Universal this fall. My dad is a larger gentleman and some of the rides he may not fit on. Also, my mom does NOT go on roller coasters. Which queues can you walk through without riding? Which ones are worth walking through if you can’t ride?
Escape from Gringotts is one that I read is a must walk through even if you don’t ride.
You can ask for a “tour” of the Men In Black area. You may even be allowed to go down to the floor and sit at a MIB desk. They lots of cool gadget & gizmos in the queue. It’s neat if you are an MIB fan.
You can do a “Castle Tour” of Hogwarts as well. This queue is worth walking through even if not riding. (This is coming from a person who usually doesn’t want to be in any queue)
Now, these unofficial “tours” may only be available if crowds are low and they have enough staff. I have done the MIB tour. However, I was willing to wait for a while to do it while they found a team member to escort me.
I believe you can walk through all the queues without riding and just take the “chicken exit” at the end.
Which ones are worth walking through is highly subjective, based on what your interests are. I am a huge Harry Potter fan, so I would definitely walk through Escape from Gringotts and Forbidden Journey. I am not a huge fan of Spiderman, but that line can be interesting as well. If you like the Fast and Furious franchise, the line is great, filled with lots of Easter eggs and other fun references. The ride is terrible, even if you like the franchise. The Jimmy Fallon ride has a lot of fun pre-show experiences that are neat to watch, even if you choose not to ride.
Lastly, as @darkmite2 mentioned, MIB has an immigration tour, the Mummy has a production tour and I believe the Hulk has a tour of some sort. These are tours that are available if there is a TM available to do the tour. They take you behind the scenes and you learn some pretty cool background stuff about the ride. At the end, they take you right to the front of the line to ride the ride if you so choose. They are not always available, but I have always asked at the entrance to the ride to see if we could get a tour.
Keep in mind that in Gringott’s you end up having to walk up a decent flight of stairs after the show stuff before the ride, which may be no fun if you’re older and not planning to ride. I will be there this weekend and will see where you can jump out of line - hopefully after the show with the Weaseley brother.