OK, so they were (at least) nice Americans. They must have so many other qualities that they have kept you communicating with them for 2 months. I hope that you had a good time.
Your advise would be much better accepted by many if it is worded differently, or should I say, a bit more tactfully. Perhaps you could have been aware that the structure of overall high school education in the States does not put an emphases on Geography nor on other countries cultures, customs, habits, languages etc. Which is very unfortunate but it is slowly changing.
SOME Americans know a bit about Geography, and then some. For example, Lausanne is almost 3 times further away from Geneve then from Montreux, and Vevey is lovely village further down the coast from you. To some Americans Vevey is known as the place of Charlie Chaplin's last days and Chateau de Chillon is over 10 Centuries young, and still beautiful. Montreux is the place of famous Jazz festival and less known for it's Classical Music festival. And Lac Leman is still served by 8 paddle steam boats. BTW, Is good old Simplon still in operation? Google did not tell me (hahahahahaha) but you could.
I shall welcome your email anytime, with any questions or a personal comment.