Something to remember when the time within the training/competition calendar seems limited for various reasons:
The higher your level of trainedness the less time you need to spend on GPP and the more of that time you may spend on concentrated training.
Thus, in a S-L for example, while the transition from indoor to outdoor may only span a couple weeks, you may very well be in suitable form for the transition if you are in a position to concentrate your training efforts earlier in the year.
When GPP only spans 7-10 days, as an example, the calendar all of sudden seems much more manageable.