I live in Raleigh near the residential only area of N Hills. Nothing big to speak of, but plenty of 3 minute hills at about 300 watts. When I was only around 200 watts, they were 4 to 5 minute hills.
I can link together other neighborhoods in town and never hit a high traffic area. I'll take the greenway for a mile to connect to another neighborhood to go grab a hill I like.
Start out with a lap of N HIlls, cross Glenwood and then go grab some stuff in the neighborhoods between Glenwood and Wade. Take the greenway to Oak Park/Glen Laurel area and lap around a bit.
I will say, these are NOT your new age crap cookie cutter 1/16th acre lot subdivisions. These are older parts of town with 1/2 to 1 acre lots and lower population density. Those cookie cutter jammed together subdivisions can be a nightmare for a bike rider.
FWIW, stoppage time on an out-of-town group ride on country roads is usually about 3 minutes per hour waiting for people to regroup or whatever. In-town, I average about 4 to 5 minutes per hour stoppage time.
I don't see many cars. If so, they're going slower. Streets in some of those parts of town are really wide.
I'm usually alone though, nobody wants to go do hills.