The 375 WIN in a 94 is nimble, powerful, and capable. Further, the Big Bore 94s were the best made since the pre-'64s.
Components are available if you search a bit. Barnes offers a traditional flat nose, Hawk is a perennial favorite, and Winchester offers factory ammo with the 200 grain bullet. In my humble experience that 200 grainer shoots flat and penetrates well-all you need for Deer. Lets' not forget Sierra, who offers a 200 grain that is also excellent.
I only know of Winchester offering brass, but it is not impossible to find if you have some patience and are willing to investigate leads.
Dies are available from Lee and RCBS, Lyman offers a pilot for case trimming, but most cases are below max length, even after several firings, so its not critical.
The 38-55 was the inspiration for the 375, but the cartridges are not interchangeable. I know there are some nutjobs who used 38-55 brass trimmed down to stuff in even more propellant, but these are the kind of guys who jump off cliffs without parachutes. You will get all the velocity you will ever need from standard 375 brass following guidelines in the Hodgdon, Alliant, and Barnes manuals.
Some years ago, John Taffin penned an article on some of his loads with the 375 for guns magazine. Its a worthwhile read, if you ignore the whining about recoil.
All in all, the 375 is so much better a woods cartridge than the 30-30 that it is notable, and I write this with a fondness for the ol' 30 WCF.
If you do decide to go with the 375, and if you have some tenacity to get the tools and components and intellectual material you need, you will end up with a rig that gets the job done, and its harder to say anything better than that.
