Pascal,

I live 40 miles from you in Lausanne. From here, I'll say that the
difference in altitude will have a huge effect: it will get you out of
the winter fog we are experciencing (for californians, an equivalent of
your marine layer), which will trap the light pollution (in winter at
least). The winter skies will be extremely clear, whether you climb the
alps or the jura mountains. 1200 m high will get you most of the time
out of the fog. Seing is not usually very good though.

Generally, in switzerland, getting up will get you tremendously better
observing conditions, because you'll get ou of the fog and smog and
generally away from city lights. Heck, I bought a chalet in the Jura
mountains for that very reason!!!

Cheers! good skies are not so far from you,

Pierre, in Lausanne