Having carried a single shot rifle (Ruger #1 .416 Rigby) as a bear gun, I will say that the disadvantages outweigh the advantages for most people. In my case these disadvantages did not relate to either the handeling or single shot issue as a falling block can be reloaded quickly with practice. I have had enough close contact experience with bears that I "might" be less prone to make a mistake with that initial shot. Over time I became concerned with the Ruger's habit of coming off safe while being carried slung. Often when stopping for a break after several hours on the trail the safety would inexplicably be in the fire position. I don't know if this malady is shared by the Browning or not, bit it resulted in having a loaded rifle ready to fire pointed at a companion's legs when carried muzzle down, my preference, and the muzzle was too close to my ear when carried muzzle up. I tried carrying the rifle out of battery but this resulted in decorating the tundra with expensive Rigby handloads. I got so that I would not allow anyone to walk on my left side. I prefer to carry a rifle without a round in the chamber, then I don't need to concern myself with a mechanical safety at all so now my bear guns are repeaters. When I suspect I might have a problem I have the rifle in my hands with the round chambered, when the problem has been resolved, the round goes back in the magazine and carrying is resumed with an empty chamber.
In your case, you will be looking for a gun for camp use, rather than one for packing around. This being the case you issue is the opposite of mine. Having the round in the chamber won't be a problem provided everyone in camp is aware of the rules. But the problem occurs should you need the gun quickly without warning. In such a stressful situation it is possible that your first shot will not be a good one. For this reason, if a .45.70 is the gun you want, a Marlin '95 is a better choice as a back up shot is only a moment away.