It really depends on what my goals are for the "off-season" of tri. I will continue to bike when I can until it gets too cold to do so because biking is fun. I will cut back substantially on swimming unless I'm trying to get major improvement there over the winter. I'll add an additional running day during the week, so that puts me running 4-5 days per week. I'll also add in some additional activities like indoor rowing (erg) and lifting weights.

So, in summary...if training for a fall running race, I'll skew my training to be very run-heavy, but usually won't abandon the other activities. However, the training for swim and bike will usually be less structured than in season/early season base

Thanks jsk and trisooner.