It sounds like you are exactly describing my to do list, Simply Goals & Tasks.
There are color coded categories (called Goals because you can say how much time you *want* to be spending on them). This way you can have a work and fitness tasks all together but still separated.
The scheduling works more like a paper planner, where you can add things to the day, the week, the month, or even just the year. This way you can zoom out to plan larger projects, and zoom back in to manage day-to-day!
And there are notifications :)