However, in setting myself up for next Mon, I noticed that I had 6 different must-dos for that day. Putting those onto the calendar (+ appointments already there) clogs the calendar up and makes it less useful for me.
Hmm... This sounds like a scheduling problem, not a tools problem. Six must dos plus appointments is a pretty heavy load. For me, at least, it's likely that something wouldn't get done, and so my solution would be to start renegotiating commitments.