Long story short, you won't be able to see everything in one trip. The Walt Disney World Resort in Florida is made up of 4 individual parks: Magic Kingdom (the main one with Cinderella's Castle), Epcot, Hollywood Studios (where the new Star Wars stuff is), and Animal Kingdom. In addition, there's the Disney Springs shopping area, two water parks, and, well, a lot more even then lol. Assuming you are only interested in the theme parks, you realistically won't be able to see all that there actually is to do. Between the rides, shows, restaurants, and other experiences, there's too much for one trip. This is be design, as to make you want to visit more than once.
1 day at each park would give you a decent taste of each park, and for Animal Kingdom and Hollywood Studios that might be enough. But Epcot and Magic Kingdom probably need at least 1.5 or 2 full days to see a good portion of what there is. Personally, I feel like a 5 day/4 night trip makes for a good vacation and the ability to experience a lot, but even then there will be a lot you simply don't have time for.
As for how long the lines/queues are, that's dependent on a large amount of factors, all variable. It's very hard to predict what lines will be like on any given day. The way to help manage this is with Fast Passes. I'm guessing you probably don't have too much experience or knowledge with that, so I would refer you to the stickied topic on the main page that talks all about Fast Passes. There's a lot to digest, but educating yourself on that will help make for a much more enjoyable vacation.