N.W.
I never took an online course at TCC (I only went on campus at TCC), but I have taken 2 at Collin County Community College. Like previous posters have said, it all depends on the course and teacher. In sociology I had a quiz and lab due each week. Labs normally consisted of a 500 word essay on interesting topics, so they were super easy to write. (Well, at least for me. I love writing.) I also have to mention... I took these classes while I was 9 months pregnant! I ended up having my daughter in the middle of the semester and was still able to pass both courses with a 4.0 English was abit trickier. We had to post on the discussion board, grammar quiz each week (super easy), and several short writings and essays. I had a very specific teacher and it made our job a lot easier. FYI, don't sign up for ANY science class in the summer. It's a very intensive pace and it's hard to get a 3.0 or higher. I studied my tail off and only recieved a 2.0 in basic biology during summer II
Before you sign up for classes, go to www.ratemyprofessor.com
Most professors are on there, even the ones who do online classes. I always double check that site before I register for classes. :)
Feel free to PM me, I will tell you who I think are great teachers over at TCC
Oh, you are fully capable of taking 2 online class and one on campus. I AM NOT bragging here (seriously, I'm not) but I am working part-time on the weekends and I have two kids and a messy husband lol!! As long as you are familiar with time management (I'm not, I am still making the transition) and get into a routine, it will be good to go.
Good Luck!