I don't play with my son nearly as much as you play with your daughter!:)
I'm of the belief that it's good for kids to learn to enjoy being alone for stretches of time. I work from home (running a preschool program) as well as within the home, so I try to flex---if he's needing time with me, he can help me with some parts of my work, or I'll set a timer for 15 minutes or so for a chunk of undivided Mama attention and just play with him. When the timer goes off, I'm back to working on something or taking a little break for myself.
Kids will often be perfectly happy constructing their own play or activities and come to us just to check in, so I let the children in my life give me the head's up when they're needing my help or support. Otherwise, it's good for them to be at their work (play) without my interruption. I know I can often work better without my son's disruptions, and kids have even less ability to multitask, so I really try to hang back, just give a pat on the back or squeeze their shoulder as I walk by them, to let them know I am aware of their presence and value them just as they are, busy and engaged in their own pursuits. This way, I don't pull them from what they are doing, and am not asking for their attention.
As for dates, my son and I do bus trips together at least once week. He's three and loves to sit on my lap. When I'm out of the house, I'm pretty solely focused on him for the 3 hours or so we are out adventuring in our town. This seems to be our most peaceful Mama/Kiddo time, so we've made a routine of these outings.
Don't forget, too, that we are human and sometimes I will go off my nut if I don't have adult contact during the day. I also use a timer (my sister does too) for the kids, so they know I'll be done when the timer goes ding. We usually allow about 20 minutes for phone conversations; when one is at home with kids all day, it's essential to have some peer conversation! Do what feels balanced and right for you, and it'll be fine.