Hello and
to the forum.
The scoop is to read the brochure, search online, visit the keystone website and search inside that site. The roof is walkable if there's a ladder, the ladder may not be climbable, it depends on your weight and or fear of heights. Check your seams often, proper maintenance is essential. Everyone runs the risk of a deficiency from the factory. That's just a roll of the dice.
Can you trust or rely on the service department of the dealership you're buying it from?
Are you self reliant?
Are you handy enough to get up there and add sealant or replace it altogether?
The whole key to ownership is whether you freak out when something goes wrong, or you are able to accept there is something wrong and move to correct it either alone or through the dealership's service centre in a somewhat calm manner. If anything goes wrong and causes you too much stress it's not worth it.
The most common major problems here in this forum are flooring or roof damage due to water intrusion. These are definitely the hardest to repair/ replace. There are not a ton of posts on these problems but when there are it's mainly the first year of ownership deficiencies, or a lack of proper maintenance.
If you maintain the unit properly you limit your chances of catastrophe.
Again, welcome and good luck