As implied above, the question is what do you want to do with this rifle?
Are you going to shoot it with the open sights or a mount and use a scope (or best of both worlds... mount a scope in QR rings and bases so you can do both)?
If you are just deer and/or average sized black bear hunting and your typical hunting range allows for 100-200 yard shots, then the 30-30 will work just fine, but go with a Win Model 94 AE for mounting a scope, or a Marlin (throw in Henry, Rossi, etc. as your preference dictates).
If you are looking at large black bears, moose and elk, then the 45/70 may be your better option. But you are going to be limiting your range on these animals depending upon retained energy appropriate to these animals (1000, 1500 and 2000 ft.lbs at the animal, respectively) for best performance. The 375 Win is a great cartridge and I have used it quite a bit on moose and black bears, but it is best kept for the less than 130 yards on larger animals.
As mentioned above, there are other lever action cartridges that I would recommend if you are mainly looking to hunt moose and elk with this rifle...307 Win, 308 ME, 308 Win, 338 ME, 356 Win, 358 Win are going to provide better performance (bullet weight, velocity, energy, penetration) on these larger animals, and provide this performance at longer distances that may be encountered, depending on where and how you hunt. It also opens up your options in rifles with iron sights that can be used with scopes (e.g., Browning BLR, Winchester Model 88, Savage Model 99, and Sako Finnwolf). Hard to beat a BLR in 308 Win, but the 358 Win is a favourite and will handle elk and grizzly out to 250 yards!
Hope this helps, and best of luck in your quest!
It is hard to beat the fun and experience of owning, shooting, carrying and hunting with a lever action!
And be aware; it is addicting! You may end up with a whole array of leverguns!