I thought of that too, probably using some 'mousewheel' event, but later I realise the page height may grow as well (with vertical scrollbar) depending on the number of events.
Maybe a hybrid approach could work? Automatically scroll down and to the right simultaneously. If I understood it correctly, the events in the timeline will go diagonally down. So if the scrolling happens intelligently by following the events, that should work, shouldn’t it?