axolotl

Well, that's not quite true, but neither is there a wide network of smaller roads, either. The truth is somewhere in between. If you look at the turistel maps I mentioned above (particularly region "H"), you'll see that there's not much in the way of north-south roads other than the Pan American Highway. There certainly isn't a continuous paved secondary route parallel to the Pan Am which covers the whole region. However, there are some sections available which are paved, and some others which are unpaved. Since I had no desire to, say, cover the length of Chile, I wasn't attempting to simply go north-south. My own route in the region was like a giant "S", starting in Puerto Montt, biking over to Bariloche (highly recommended route involving 3 boat trips), then back into Chile (that pass has now appears to be paved) to Valdivia, then back eastward to Pucon, then up to Temuco. I also did some riding way down south around Punta Arenas as well as the Valparaiso/Vina del Mar area, and around Santiago. I did bike a couple of short stretches along the Pan American and it was noisy with lots of traffic, though I was able to ride entirely along a paved shoulder. Still, not my idea of fun. Also, it was unusually dry when I was there, and the unpaved roads were annoyingly dusty, though traffic was generally light on them.

If you end up going to Chile, I would recommend that you cross into Argentina for at least a few days. The culture is quite different from Chile, and Argentina is now a cheap place to visit. Be aware, however, that much of western Argentina is very sparsely populated and you'll have to plan your route carefully since you don't want to camp. (I understand where you're coming from. I didn't want to camp either, and was glad I was able to do my trip there without shlepping camping gear.)

Questions to consider are what month(s) do you want to travel? What are the most important attributes you're looking for: Scenery? Culture? Safety? Good food? Chile rates very highly for scenery & safety, including hygiene. The culture & food are less interesting. Parts of Mexico have good scenery, other parts are so-so. Some parts (e.g. Yucatan) are very safe, others less so. The culture is always fascinating in Mexico and the food is superb. The Mexican people are outgoing and wonderfully friendly. Chileans are nice but very reserved (the contrast with Argentina is striking when you cross the border) Ecuador has some great scenery, too, and an interesting culture. Unexciting food. The people are quite reserved. I'm honestly not sure what the safety situation is like these days, but in the past, Ecuador was a safe country overall.