You mean to tell me there is

You mean to tell me there is not one person here that has never built a " Limited Editions Passenger Car Kit?
 "

I've never hear of "Limited Editions."

Are you building removable roofs on the on the cars?  Except for dome cars, and modern AmTrak superliner cars, passenger car windows are relatively small.  The detail of full interiors will be lost unless your roofs are removable to allow people to see inside.  Are you modeling a from a prototype, or freelance?  If you are modeling freelance and you are not going to have removable roofs, you are the interior designer.  Put in bulkheads in your sleepers to divide them up into roomettes, drawing rooms, etc, and decorate them with the colors you like.  If you are modeling from a prototype, try to find color photos of the interiors of the actual passenger cars.  You don't need to do a lot of detail, only what is visible through the windows.  For a dining car, I often cut the legs off of sitting people at the knees to make them fit the car better, and just glue a rectangle of styrene on top of their legs.  A couple of details on the table wil bring the scene to life without needing to "go crazy."

If you are building a model for an NMRA contest, you will probably want to make the roof removable and go to a lot more detail, but for an operating model railroad, just make it good enough to be convincing.

As far as the trucks are concerned, do you have prototype pictures?  Do you know what your prototype used?  If you give us the prototype information, someone may be able to steer you in the right direction for trucks without needing to know anything about who made the kit or how it is constructed.

Limited Editions Trucks

This topic is covered in the files of the Espee Yahoo Group.  Recommend you consider joining that group to see all of the discussions available on the trucks for these great cars.  The topic has been covered there in extreme detail