Some of the IGH's have a minimum ratio between chainring and cog, roughly 2:1 as I recall. But I wonder if that's really going to be a problem for the OP. That limit has to be based on the anticipated weight and strength of the rider.

Reading between the lines, if the OP is struggling with moderate hills in a residential neighborhood, then they are probably not a candidate for pushing the hub beyond its mechanical limits. In this case, I'd tell them: Go ahead and try a smaller ring in front, know that there's a limit for good engineering reasons, don't overdo it.

I've never heard of anybody breaking an IGH due to too much torque. If they're that strong, they've probably already moved to derailleur gearing for other reasons. I'm certainly not that strong.