2011/05/10:
A word of advice (updated):
Not only should one do things in the proper order (returning to college
while working full-time is one heck of a balancing act), two classes is
pretty much the practical maximum. I've done three for the last two
semesters (the reason is unimportant), and it has been flatly
overwhelming.
Don't backfill if you can avoid it -- and don't overload if you decide
to do it :-)