Hi Tcp03! Personally, depending on the course, I spend about 1 or 2 hours a night for Aspen courses, and can usually afford to take a day or two off of my coursework during the week. Some courses are harder than others, though. I spent a good 3-4 hours a day, 7-days a week on Accounting because that course was more difficult for me.
As far as tests, the only test is the proctored exam at the end of the degree program. For math-related courses, problems are completed in each module and submitted through Excel.
If you can afford up to 3 hours a day (maybe less) of extra coursework, I think Aspen would be a great option for you.