I figure the caboose would run around $40 if done in RTR. It's such a unique prototype, yes it covers many paint schemes and a long history but it still only applies to realisticly one road and a couple offshoots.
The SP bay window at least resembles some other prototypes, the Wagontop us uniquely B&O and would pass for nothing else.
I'm paying $50 per for CN Pte St Charles vans (caboose)... not bad RTR when the Athabasca kits are almost $40 per, and all the trimmings are extra (decals, trucks, couplers, etc). Happy to pay that price for this unique prototype.