your winter plan depends on when your first races are and also, your fitness level. I like to take 6 weeks COMPLETLEY off the bike (september-october 15 ish) In this time, I go to the gym only 1 or two times a week. And try and do a lot of EPIC stuff. For instance I did an 8 hour hike the other day. I try and go running and do a lot of core, and keep in generaly good shape, and refresh my mind. By the end of 6 weeks, I hate running more than anything, and cant wait to bike again. this year my schedule looks like this (designed by my coach and I)
First Race (first weekend in march)
(all 6 days a week and all under 80%)
My first ride is only 1 hour long. For the first 3 weeks I add 20min each week to ride length and get to 2 hours by the third week. Then I add 10 min each week until I get up to 4 hours per ride (early-mid januarry). (there are also some days scheduled to take off and even a week here and there) In mid january I am at 20-25 hours a week. The plan is to throw in some longer easier intervals around 20 min mid january two or three times a week. Febuary will have some intense intervals in it. And then come march Race weekend provide intervals (tt, rr, crit) almost every weekend, and maybe an easy mid week interval, and lots of base miles.
the winter is perfect for gettin base miles. As long as you start early enough. Starting to late means that you have to start off to hard, if you want to be prepared for your first races. Base miles are like putting money in the bank.
Nordic skiing, running, and lifting are all excelent ways to get in shape, but there is no substitute for time on the bike. NONE
I live in vermont, so I am well aware of how [censored] the winters can be. I try and ride outside everyday the roads are dry. And 4 hour rides in february are pretty intense when its only 10 degrees outside. That being said, i did ride close to 3500 km on the trainer and rollers last winter.