October for riding alpine passes- too late?

So I’m thinking of a little holiday having a go at a few of the Alps classics, maybe basing myself in Bourg-d’Oisans or somewhere. But it looks like my window will be mid-October and I’m wondering whether that’s going to be a problem?
I appreciate that there can be huge yearly variation for when the snow starts but apart from shorter days and chilly descents is there anything I should know?

Also, recommendations welcome for routes/bases/accommodation etc. Bourg-d’Oisans, Alpe d’Huez etc. are the honeypots but I’m as interested in good rides in nice places as ticking the big names.