Middle child guilt

My middle child is 5 years old. She's 2 years younger than her sister, and 3 years older than her little brother. She just finished preschool and since she was only attending 3 mornings a week, she was with me a lot of the time. Although a lot of that time we're running around doing errands so it's not really fun quality time.
When we actually were home she an her brother would play together and as soon as he went down for a nap, she'd ask me to play with her. As much as I could I would but at the same time the time I have with only one kid awake in the house is also when I can get the most done in terms of tidying up and other chores.

I feel bad cause when her older sister was the only kid in the house I had plenty of time to sit down and play and read stories.  I do my best to give her extra attention when I can, and if she wants to play a game and I have a bunch of stuff to do, I tell her what I need to do first (usually tidy up the kitchen after lunch and start a load of laundry) and then I can play.  I also try to tell her that as much as I'd rather just play, sometimes chores come first and then play.

I also think I take for granted how well she plays independently. I leave the pretend play (dressup, playing with princess figurines etc) to her and her sister cause that doesn't really interest as me as much.  I'd much rather play a board game, do a puzzle, read a story or do a craft.

I also know I'm harder on her than I am on her sister, but I also feel like sometimes the way she acts is a way to get attention, when she really does know better.  Our play area is in our basement, but it's also where our TV is.  During the day, I hardly ever go down there.  At the end of the day the kids are expected to clean up their toys and the two older ones can get ready for bed all by themselves.  Most nights my oldest will come to me and say her sister is just playing and not helping clean up.  Or once they make it upstairs to get ready for bed, the oldest is doing everything she needs to get ready, and the middle one is taking her sweet time.  When I go up to check on them and ask what she's been doing most of the time the answer is, "nothing".

We have a story cutoff.  If you're not ready for bed by the time of the cutoff, you don't get to have a group story.  We still let them read in bed, but just no time sitting all together reading. It seems to bother her when she misses it, and often the next night she will go faster, but then the following night back to her regular ways.  When she is ready in time, we praise her, especially when no bugging was needed, but the positive reinforcement doesn't seem to work either.  So often times I go from what had been a good day to tucking her in at the end of the night feeling guilty cause I was yelling at her.  I guess I could try a star chart, but feel like that shouldn't really be necessary.  Although she is still at the age that all those little trinket prizes still make her happy so it would probably work (until we take the chart away). 

This fall she's starting kindergarten which is half day but 2 days of extended day care where she will take the bus to a different school, eat lunch there and then I'll pick her up around 3.  She's very excited for these long days but I know I'll have a harder time balancing the good time with her again, although am excited to have some extra time with my son.  I know parenting is all about balance and we all struggle with giving the kids the positive attention they need.  I have it relatively easy compared to some since I don't work outside our home so I have more time in the day to do these things. I guess the main thing is to channel the guilt in a productive way, and turn it into positive energy and find more time.