230-350 miles weekly between March and October. 150-250 miles weekly between November and February. I think you can train more effectively indoors in winter, but that's only if you can mentally handle it. I enjoy riding outdoors, and I've even started to enjoy dealing with the elements, which I've mostly gotten a handle on. Some days you can't ride, like today, when there's frozen precip and the roads are too dicey. This year I'm hitting the gym 2-3 days weekly, and somewhat harder than in previous years, I think it will help.
By January I will even be sporting a sixpack, and the Ladies of BF will swoon even more than they do now. Today was my 5th workout, and for the first time the core work wasn't killing me, so it's coming around.