Hope you didn't see any "smoke on the water"...
Montreux's at the other end of the lake, so it probably would have been hard to see the smoke even in 1969.
7h-23h , not sure if the gate is locked if you turn up earlier than that. I've only been during the dawn concerts, unfortunately over now. The 10chf breakfast is decent.
Rhone is also good, from the other side of Pont Sous-Terre.
That definitely looked promising.
Saw somebody swimming/floating down the Rhone this morning - is jumping in and letting the current carry you kilometres downstream as much a thing to do here as it is in Bern?
Going past Jonction (where the Arve joins the Rhône) is possible but not really recommended, and between the lake and Sous-Terre is a *bad* idea. Inflatable boat from Sous-Terre to the passerelle du Lignon (pedestrian bridge a few km downstream) is popular. Jumping off the Sous-Terre bridge is also popular. Some people jump off the passerelle, but that's getting properly high.
Btw, BdP also does good lunch.
Chairman Mao managed quite well in the Yangtze.
Lignon and Sous-Terre both featured in my run this morning.
Once saw someone in Thun jumping out of an upper-storey window (not sure if it was 2nd or 3rd) directly into the river.
And you learn something new every day (thanks to Google Maps) - in the Walliser dialect of Swiss German, the Rhone is known as the Rotten.