Re: Level Design Planning Help
Your plan doesnt have any obvious gaping holes. I think the main advice anyone would give you is to make games / design levels, which you seem to be aware of.
I'm graduating from a 4-year university next month, and I have tried to follow the path you're essentially taking, but aimed at becoming a game designer/programmer. I majored in philosophy and have a minor in computer science. I can program relatively simple 2D games with Flash, and have some experience with Unity. What I wanted to say is that it is hard to build a portfolio for yourself completely extra-curricularly. It can be very hard for a lot of people to motivate themselves to work on things their classes aren't requiring them to do. I know one guy who has done it very well - he has 3 nice puzzle games in the Android marketplace. There's myself, who has done an okay job but could have done better, and I know 2 guys that are pretty much failing at it. If you don't have a history of taking the initiative and doing lots of work that isn't required of you, you may want to re-evaulate your ability to teach yourself game development totally on the side. That side, I have become a much more proactive person since having to teach myself game development, so there's that.
I'm not saying you should go to a game development school, but if you did you would statistically have a greater chance of having a nice portfolio upon graduation.
But you should check out what majors your school offers that would be interesting that would also let you make game-related projects. For instance, does your graphic design department offer 3d-modeling classes? You could make game-related assets or levels in those if so. The advantage here being you have deadlines you're forced to keep.
I would definitely recommend the minor in CS. Tons of jobs in a variety of fields are looking for programming skills these days.