I can't comment on CSR, but over three stays at SOG, I've only seen a bus fill to capacity twice. Once was for morning EMH at HS, and they had a second bus ready to go at the same time (and there ended up with like only four people on that one!). The second was for coming back from TTC (and I think it was after evening EMH at MK, which ended at 1 am), and we all got on (and the bus driver told us riddles the whole drive back, which I think was a very smart distraction technique!). I think some people are put off by the schedule aspect to SOG buses from HS/AK (1-2/hour, depending on the park), but we've never had an issue (and you can always hop a Polynesian bus and walk across the road!). They give you a paper copy of the schedule at check-in, so I keep that in my bag.
SOG is quiet (or at least, we've never had noise issues!) and the rooms are spacious. All rooms have either a patio or a balcony (with chairs). We have three adults in one room, and my dad takes the sofa-bed and loves it (he's 5'11, so not short. The sofa bed is only single width though, as it's a flip up type bed).
Just remembered that you got a FD bounceback--does your $300 difference include food costs? You're not able to add Disney dining plans to SOG rooms.