Well as I mentioned, the ones in the Queen's apartments are more like "Juliet balconies" - ie. French doors open and there's a shallow space to step outside, but not a "proper balcony". I'm looking at the floor plans right now, and see that quite a shallow one runs the length from the Queen's Bedroom, past the Anteroom, Sitting Room, and the adjacent two rooms (which in my old plans are labeled "Audience Chamber" and something else). Another, wider balcony runs the length of the Duke of Edinburgh's apartments further east along that range.
There are four somewhat more "proper" balconies along the west front, from the Sheraton Room (at the northwest corner), the Royal Closet, The Blue Drawing Room, and a small staircase room just south of the State Dining Room.
As far as the guest rooms on the East range, I just looked at my plans and see that my earlier post was incorrect - I said there were 3 bedrooms in between the Yellow Drawing Room and Center Room, and another 3 rooms between the Center Room and the Chinese Dining Room. I now notice that (at least, at the time of my Victorian era plans), there are actually more rooms than that.
Just north of the "Yellow Drawing Room" the plans show a small "Writing Room" (with an attached bathroom), then 4 connecting bedrooms without baths (two labeled just bedroom, one called "Green Bedroom" and one "Red Bedroom"). Then a small "Dressing Room" (with another attached bathroom) before you reach the Center Room. Two water closets are also shown at either end of this section of the principal corridor (on the Quadrangle side across the corridor from the bedrooms).
North of the Center Room it shows another small "Bedroom" (with attached bath), followed by two larger "Bedrooms", then a "Sitting Room", and finally another small "Bedroom" with a attached bathroom. Another pair of water closets are across the corridor. Past this is a staircase, and finally the Chinese Dining Room at the northeast corner.
But I wouldn't be surprised if these rooms were reconfigured in the 20th century to add bathrooms.