When ever I hear of shut in cartoonists, I can't help but be reminded of Howard Stern verbally beating on a freelance graphic designer.
Only thing hard about it is not becoming a worthless, self-important person. Which is pretty easily solved by stepping out of your house/minimal part-time work via temp agency.
I've always found it the opposite for me, the periods of time when I've worked exclusively from home have always affected my self esteem poorly, which is why I try to keep a part time job (preferably some kind of specialty retail) whenever possible - interacting with customers in a shop is great.