Ball Python blue print critique

I plan on building an enclosure for my Ball Python shortly. She is only about three and 1/2 months old, but I want the enclosure to last her for the rest of her life. Here is what I have come up with so far, tell me what you would change/add.

Length - 48in (4ft)
Depth - 24in (2ft)
Height - 24in (2ft)

I'm not sure yet what I want to do with the front as for how it opens and closes. I plan on bracing the inside of the cage with 2 x 2. I'm not sure if I'm going to keep that 4' substrate dam. Here is a scretch, what should I add to the materials list? Please critique!

http://img65.photobucket.com/albums/...ckey/plans.jpg

I am working on something similar, although for Ackies rather than a BP. I would go for a sliding glass door in the front. Also, if you're going to use a heat pad maybe you should add some feet onto the bottom so you don't have to bother finding something to rest it on top of.

Okay, is there anything you would change? I want to add sliding glass for the front but I'm not sure how to go about doing that.

Anyone help me out?