My previous plans are SweetSpot Base Low I+II, Sustained Power Build Low.
I want to increase the average speed of the regular outside ride each week, a 300m high hill climb(usually on Wednesday) and a 100km endurance ride(Usually on Sunday).
Without your end goal being a race I would almost say just go back and start the base/build cycle again. I feel like that will get you your biggest bang for the buck since the goal efforts you’re talking about happen frequently.
Is you FTP improving? I agree, go back to SSB then pick a build plan. Maybe General Build to mix things up since you have a short effort goal and an endurance ride goal. General Build works on both energy systems. That being said, you can always do a Specialty Plan (Climbing Road Race, Rolling Road Race) and then go back to Base / Build / Specialty. Since you’re not targeting anything specific, your choices are wide open.
If you see that your FTP is starting to stagnate, you may need to add in more TSS. Possibly move to a mid volume plan or fit in some extra aerobic rides when you can.
In both 2017 and 2018 I have done the LV Century Specialty Plan after completing LV base and build, with similar goals of just getting faster on long outside rides. I really like the LV Century plan - challenging workouts but nothing intimidating after completing a sustained build, and the late plan VO2 workouts with 4 to 5 minute intervals around 110/115% are unlike anything in the LV base and sustained build plans which keeps things interesting.