How Much is Enough? Too Much?

I'm doing lots of planning for the upcoming year, as are most homeschoolers I'm sure. The thing that's driving me insane right now is determining our general schedule. I'm massively conflicted about it. Actually, our *general* schedule is lovely, it's the reality of the scheduling *specifics* that are tricky. Generally I want us to have a three hour uninterrupted work period in the morning after breakfast, then a couple of hours free play and lunch, then Pre naps while Kinde and I do a more directed or involved project like science experiments, then more playing until dinner. See? Lovely. Ideally, free play period would be three uninterrupted hours as well. The trouble starts when you add in our classes. Here they are, along with their justifications:
----------------------------------------------------------------------------------------------------------------------------
Swimming - feels like a non-negotiable safety issue until both girls are competent

Guitar - the extent of our music education (and all that I plan for the future beyond CM style appreciation and singing a few folk songs at home)

Creative Dance - excellent class that Pre can take too!

Hike - not a class, but a family priority, especially as we are more likely to otherwise stay inside in the winter and I feel like hiking is a great way to grow strong, confident girls

Irish Step Dancing - Kinde has been doing this for a year now and both loves it and is quite good, I love that it is a style of dance with a reasonable culture around it (don't destroy my girl!), it's a social style of dance, and it can be a lifelong physically active hobby (unlike my gymnastics history).

Drawing with Children co-op - Great opportunity for progressive art education with a friend and respite for both from little siblings, as well as for littles to actually have an activity planned around their interests and abilities. Will shift to Atilier once drawing lessons are completed.

General Co-op - an important place for us to make strong connections with a few families, and my kids benefit so much from exposure to the other main mom.

Spanish Preschool - an unusually good fit for our kids who understand lots of Spanish but don't speak much, right in our neighborhood. Second language a big priority.
----------------------------------------------------------------------------------------------------------------------------
What this leaves us with is just three mornings a week for a good Montessori work period. Is that enough? I'm not worried about covering enough material, I'm certain they'll learn plenty for their ages between that, their classes, and the additional one-on-one time for Kinde. I'm worried about if they have enough time to explore the materials and learn the far more important lessons of self-directed and self-motivated learning. Speaking of enough, is there enough time for totally free play? I'm feeling like it's all a lot, but can't talk myself out of any of it. Also, we are in the car Every. Single. Day. Ugh. (Though we are investigating a move that would knock out two of those.)

Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
8 am Montessori	Montessori	Montessori
9			Spanish (Kinde)	Co-op
10					Irish Step Dancing (Kinde)
					Spanish (Pre)
11
12
1
2					Rosetta Stone	Rosetta Stone
3	Drawing with Children / Preschool Art Co-op		Creative Dance	Hike
5 Swimming (Kinde)
6 Library Time		Guitar
7 Swimming (Pre)
8 Bedtime	Bedtime	Bedtime	Bedtime	Bedtime	Bedtime	Bedtime
Athletics
Pre naps 1-3
Co-op
Montessori
Spanish