The local orienteering clubs offer a choice 2 km (beginners), 3-4 km (intermediate), 5-6-7 km (advanced) courses all according to skill, endurance, speed, whatever. Lately I've been taking only those 3-4 km courses as my speed is what it is (15 + min /km). That is sort of average among the local hobbyists (or somewhat below, if I elect a tougher course). Of course, the athletes do something like 8 min/km, and (depending on the terrain) world class runner do around 6 minutes/km. The local terrain is relatively flat with patches of marshland interspersed with rocky areas. Mostly wooded (this is Finland, after all) of varying density of trees.
I would expect you get more variety in type of terrain in the US (or central Europe, or, for example Norway) than what I'm seeing here. In Finland you get very different terrains, if you go the areas where there are eskers, ridges and other formations dating back to the ice age, but locally it is more monotone (altitude variations about 100 ft or thereabouts).
This year my streak of 13 years of participating
in our annual main event came to an end due to my foot injury. In that relay I have done legs between 8 and 12 km with more warying terrain (12 km is like a marathon to me). My teammates are somewhat faster than I am, but they don't
seem to mind too much.
Did you do orienteering while serving in the army or how did you get interested? IIRC it is not a big sport in the US, though it could become so, if suitable terrains are found within, say college towns.