The issue is not the main roads, but the last few kilometers to get to places to visit. The question is, "What are your limits on the Strom?" In Peru, which is the majority of my SA experience, most of the ruins I enjoyed were on gravel switchback roads. In the Cusco area, the difference is choosing to explore Machu Picchu or Huchuy Qusco, or visiting ruins/sights in the northern Peru highlands route (access more challenging), vs not. If you're not super dedicated to road challenges on the Strom, you might start to bypass those places because of the challenges. Detours: they happen, and they are tough on a 650cc moto; mud, steep hills, narrow roadways. Off the PanAm, where you experience the local culture, there will be unexpected issues; stream crossing, mud for sure, bumpy rock filled road, narrow pedestrian bridge or landslide detour vs turning back. Sometimes available overnight parking for a bigger moto can be a challenge to access. Narrow blacktop roads: You will meet a bus or truck in a hairpin turn on a one track wide mountain road, and being nimble is paramount, even when traveling at 25 kph. These are the main roads, off the PanAm. They are blacktop or good gravel. Unless you do not plan to explore off the PanAm, these issues are part of the choice to leave the PanAm.

It all depends on what you're looking for, your passion level to explore unknown places, and what you want in a moto. Some folks like to make miles and spend time in cities at backpacker hostels, drink cerveza, and such. They stop at sights that are easy to access. Others (obviously my bias) look to get away from the tourist track, which now and then involves road challenges. In SA, the condition of the PanAm is like the State highways in North America, and the well used secondary roads are like township and county roads. The Strom will be a challenge now and then off the PanAm, but it will easily shine on the better roads.

Buen viaje a tu!

As an edit, "a picture is worth 1000 words" Peru highlands route:

Muddy tires from ascending switchback access to ruins at Chachapoyas


Road construction on Highland Route in Peru:


Wait 6 hours in the rain until evening or take this detour:


And this is some of the great riding:


And of course, plenty of this:


And this:


Plus this: