"Look up Lake Titicaca, when you have spare time... "

Well, I first thought I knew this lake, but it's a different one.
This one is about 15 S Latitude.
"Lake Titicaca is the world's highest lake navigable to large vessels, lying at 12,500 feet (3,810 m) above sea level in the Andes Mountains of South America, astride the border between Peru to the west and Bolivia to the east. Titicaca is the second largest lake of South America (after Maracaibo).

In 1862 the first steamer to ply the lake was prefabricated in England and carried in pieces on muleback up to the lake. Today vessels make regular crossings from Puno, on the Peruvian shore, to the small Bolivian port of Guaqui. A narrow-gauge railway connects Guaqui with La Paz, capital of Bolivia. The world's second-highest railway runs from Puno down to Arequipa and the Pacific, completing for land-bound Bolivia, an important link with the sea.

The lake averages between 460 and 600 feet (140 and 180 m) in depth, but the bottom tilts sharply toward the Bolivian shore, reaching its greatest recorded depth of 920 feet (280 m) off Isla Soto in the lake's northeast corner.

Titicaca's waters are limpid and only slightly brackish, with salinity ranging from 5.2 to 5.5 parts per 1,000. Surface temperatures average 56º F (14º C); from a thermocline at 66 feet (20 m) temperatures drop to 52º F (11º C) at the bottom. "
http://www.crystalinks.com/laketiticaca.html

Now, I does appear to have some transportation infrastructure- a nearby port (about 250 miles) with rail line up to lake. One problem is if you wanted to do a Eastward launch, it looks like you couldn't avoid going over populated areas. And second, the lake depth is somewhat limiting- fine, for a mini pipelauncher, but not enough for larger pipelaunchers. With suborbital flights, you could have the rocket path going across the length of lake, if your destination was Buenos Aires or the large Brazilian cities, or northward towards Lima or further to the Galapagos. Now, if appears this is a tourist destination. A pipelauncher could actually have an advantage as far noise levels- the pipelauncher itself makes little noise- and could put the launch site 20+ miles from and any residental areas. Also rocket wouldn't *neccessarily* need to attain supersonic speeds quickly- plus it's going vertical, so most of noise would directed towards the water. The rocket wouldn't need to reach supersonic speeds quickly because instead of having take-off acceleration at around .6 gees, since the rocket has been accelerated, it could safely have lower acceleration take-off speed- say half this: .3 gees (the engines going full, but it's "overweighted"). So it's profile could be if it climbs straight up for 20 seconds after leaving pipelauncher, say with average .4 gee, you would be +2 km high and going around the speed of commerical airliner.
It wouldn't be "quiet", but it's possible it could less noise to less people than normal commerical airport. Being less than a hour from some of South America largest cities or to another tourist location, would probably have an economic benefit to this area.
And could feed the myth in area of the gods ascending to the skies:)