Question was perfect walking rifle and you answered:
I assume you mean something like this shotgun of mine: H&R model 176 10 gauge, full choke, with 36" barrel. It's only a single shot but then you don't have to shoot this one very often.
Seriously for what the man was asking for a lever gun in .357 mag will fit the bill just fine. 148 gr wadcutters 38 spl for small game and 180 gr full load .357 for midsize game and he will be able to cover everything he wants to shoot in a light easy to carry quick to shoulder and easy to shoot gun. In addition there are all the other bullet styles and weights that he can pick and choose for optimum accuracy for his gun. Shotgun was kind of generic don't you think?