Drum brakes stopped cars for a long time before the across the board application of disc brakes. You just have to know the limitations.
First, drums do not give up their heat as rapidly as discs. During repeated or continuous application (going down a long grade, for example) the drums will actually get hot enough to reduce the coefficient of drag to the point that the vehicle will not stop. Brake fade. You have a high hard pedal that basically does nothing. I experienced it on a 68 Suburban. The drums were slightly beyond the maximum allowed inner diameter. I was hauling my drag car on a trailer which did not have the brakes hooked up. It was 108 deg. outside. I was throwing it in low, standing on the pedal with both feet, pulling on the steering wheel with both hands. And my wife was worried about me driving the drag car!
Water, particularly deep water, say 1 - 2 feet deep, can create a similar situation. The drums fill up, the water drops the coefficient of drag, and you have brake fade.
So, if you know the distance required to stop and adjust your driving habits accordingly and pull over occasionally to let the brakes cool down or dry out, you should be fine.