After Guanta the surface reverts to a relatively stable and rideable dirt surface. There are no formal services (food, water) etc. between the town of Guanta on the Chilean side and Los Flores on the Andean side, many kilometers away, so make sure you have enough food to get you thru this region. The water is drinkeable from the streams at the higher elevations, so you are OK there. It is possible to get some bread and other simple provisions from shepherds in the region, as well as at the border crossing points, but these are strictly courtesies of a friendly people and should not be abused.
The climb is not a steep one, but is relentless. The mountains are dry and barren, though colorful; and snow appears as you approach the higher parts of the pass, especially in odd ice formations known as Los Penitentes. These narrow and seemingly kneeling ice sculptures form due to action of the wind and sun. The air is cold enough for the ice to remain frozen, but the sunīs rays at midday can melt the surface; so only the surfaces parallel to the noonday sun (or the prevailing wind) survive. The result is a series of very narrow ice sculptures which, at a distance, appear to be throngs of kneeling and penitent Christians on the mountainsides. Think about that as you struggle up the pass in the thin, cold air. I have alot of riding experience so I did not have the headaches many riders get at these lofty levels; but I was giddy, and my front tire kept sinking into the soft sandy roadway, so I walked most of the final 10 kilometers or so to the pass. Mountain bikers may have better luck.
MAYBE...maybe mountain bikers will have better luck. But then again, I know many mountain touring bikers who, enthralled by the strength of their machines and their versatility, pile the weight high and deep in their panniers, front wheel and back. So it was with the fellow here, who I met near the summit of Cristo Redentor. He was on a tour of Chile and Argentina, going in the opposite direction as I, and we spent a night together at the Hostal near the summit. There, as the temperatures fell below freezing, we put our food together and had a nice meal of soup, spaghetti, bread, tea, chocolate and cookies.
There is an old railroad that follows the route, falling into serious disrepair on both sides of the border. The railroad has its own tunnel thru the pass, which is now the one used by cyclists who come this way. Though lit, it is dim and dank and I encourage cyclists to walk. Again, the signs say it is 4 kilometers in length but I think that is an overstatement. The light at the end of the tunnel, and the lengthy descent to Vina del Mar on the Chilean coast, just glimmers in the photo below.