Help me set my bike fitness up for next year

I intended to do Jorge's plan after getting my trainer last fall.  However, I found that simply riding a good hard effort on the trainer for 45min 5 days a week (initially) was plenty tough without throwing any intervals in.  If your cycling base isn't built up too much yet you could see huge gains from just riding a lot over the winter.  Find some good TV shows and movies and DVR everything.  Don't allow yourself to watch any TV unless you're riding the trainer.

If you can handle the intervals then go for it; you'll get stronger i'm sure.  However, the steady hard-ish pace will absolutely build your aerobic and cycling-specific endurance base.

To put up one idea, this has worked well.

How much time will you have after the marathon? Not everyone's definition of "bike focus" is quite the same. Could get some more variety in there as the link could be rather taxing mentally.

I think Jorge's plan is a good start for most people.  But I'll doubt you'll be able to jump into it right after your marathon.  You'll likely need a couple of weeks to recover as those workouts are pretty intense.

Man, I gotta say - I consider myself pretty tough in terms of HTFU, but 2 x 20 @ FTP is really, really hard. Demoralizingly hard for me, actually. It sounded like easy stuff, but it's so hard that I am far more willing to do a 2 hour ride at a lower effort than 2 x 20 at essentially all-out pace. That's some serious suffering. 

Yes, this actually has you going closer to 95% for 2 x 20. Still rather hard though. The 1 x 20 you beat FTP, going after 105%. They aren't kidding about the "you will want to be done". These also fit rather well into Sufferfest videos. Hell Hath No Fury, The Hunted, A Very Dark Place. AVDP is actually 5 x 4 min, but close enough. It's 20 min total of seriously hard work. You find out that "tunnel vision" is very real. Sometimes I'd switch in Revolver on the second day. 15 x 1 min.

I used their other videos, but didn't really go all in that often like on these. Typically going 90-95% on the work sections and 70-75% for the recover. And do 2-3 vids in a row. That's why I ask about time available. Another option is looking into sweet spot training. A little lower intensity, but longer work periods. The two Extra Shot videos worked well for this.

The link above is a good place to start (and stay with forever)

Plenty of time after the mary.  Commuting ~20 miles each way 3 days a week to work comprised of a warm up and then hammering the rest of the way.  I can add a two or three 2+ hour rides during the week, fast mid length (40-60) mile group ride on Saturday and plenty of time on Sundays to try to hang on the wheel of some of my much faster friends.  

Also adding a trainer to the stable for times when necessary or beneficial.