I think passenger cars did not go off line as much - except for express cars which are considered passenger cars.
coaches especially stayed on line in most cases. They were generally used for shorter trips and were lower priced accomodation.
Pullmans run by pullman, or by the RRs after Pullman was broken up, probably did move around but on specific patterns. For example trains on the PRR from NYC might have a sleeper or 2 for Florida that they take to washington DC. the sleeper would be transferred to the Southern, ACL or SAL to continue to Florida. Stuff like that happened in Chicago too with through cars going to the SF or UP or somebody else I think.
Freight cars went everywhere however. Remember, the majority of manufacturing in steam days was in the East and probably the north. PRR, NYC, B&O and a few others were probably the source of a lot of goods flowing west and south. PRR had over 40 thousands X29 boxcars alone, more that the entire fleet for some RRs. It would be possible for them to go anywhere in the US I would think. Reefers probably flowed the other way loaded. Fresh produce from the west and south flowed to the major population centers in the norht and east.
Hoppers most likely did not move as far afield. Gons and flats somewhere in between moving heavy goods.
Look at videos of RR operations and note the mix of cars. Study pictures of freight yards.
