Winter bike training plan

Hi everyone,
Does someone recommend a good off season/winter training plan for 3 sessions/week (something like 2 indoor/1 wkend ride) ?
The aim will be a season of half IM with 1 full IM (main goal)
I tried the British Cyling base building last season, good plan I think but it was hard to keep the intensity while still running and swimming.

Thanks a lot
Ivan

Have you looked into any of the Trainerroad plans? Lots of options for base build for both HIM and IM. 8-12 wk plans.