With my kids it was never a problem to just let them sleep wherever we happened to be sitting (restaurant chairs, museum benches, bus seats, a patch of grass, my lap, ...). Occasionally I was stuck carrying a sleeping kid around for a while, but that was also typically fine. A stroller might be mildly more convenient on rare occasions, but it was never a big deal, and the kids becoming self-sufficient much earlier and more completely (with respect to mobility) than most of their peers was more than worth any trouble. YMMV.