We have a mix depending on which way I ride from the house. Flat it ain't. We have rollers, where you can almost get up enough speed going down one to get most of the way up the next one. We have short 1/4 mile, steep grades, some times these are in steps with a slightly lesser grade in between them. Depending on the bike and the load I may get off and walk up some of the worst ones. Otherwise it is "put 'er in low gear and grind away" I gear all of my bikes pretty low, I am getting old and want gears on the low end, not the high end.
Aaron