What is the alt-right, exactly? If it's "a euphemism for white supremacy", etc. then it's nothing new and we can drop the neologisms and just ask if there's a distinction between young conservationism and white supremacist conservatism. I think we all know it's a little more nuanced than that and that this isn't all that the alt-right is. If it's the new fascism, then there are like 6 or 7 actual alt-righters in the country. White supremacy has pull. No one is an actual fascist.
If conservatism is about maintaining the existing order, doesn't that imply hostility to immigration? Doesn't it imply white supremacy? The United States was founded by, populated primarily by, and has always been pretty much run by northern Europeans, yes? Isn't it kinda silly, maybe even a little dishonest, to call yourself a conservative and claim to be at best ambivalent about maintaining the status quo on this?
The youth have always populated the political fringes. The Bolsheviks in Russia were kids. Look at who's doing the Islamic Fundamentalism-ing.
There's nothing new here.