One way to look at this might be – what would it take for your summer climbing plans to be mostly capacity-building? Like you said, using smaller mountains and shorter climbs. If you aren’t looking to build up to one peak (one major event or window of peak fitness), then periodization becomes a bit less important.
What would a typical summer week look like for you? If you’re training 15 hours per week, as an example, and the smaller hikes / climbs that you’re thinking about are half-day endeavors, then you could perhaps just think of those as your long aerobic workout for the week, 20-30% of total volume.