to be honest with you I think that if you want to get a good mark then you are being overly ambitious with what you want to achieve (bearing in mind that you are using maya for the first time). You are looking at at least 3 major areas of CG environments, Character Animation and Particles/Paint FX You would be much better advised to drop probably two of those and concentrate your efforts on one. It takes a lot longer than yo umay think to get this stuff right and it's one of the things I've seen over and over again where people try too much instead of concentrating on one thing and doing it really well. e.g.

Lets say you do all three and have floursacks and deserts etc and you do then in a mediocre manner where nothing is particularly great. What sort of mark will you get? not a particularly great one.

however if you do just a floursack (or two with different accesories) or just the desert then you can really go to town and make it look great which IMHO will get you a great mark (well it would if I was marking it )

For me if you just did the floursack with some nice (SIMPLE) animation on it and render it really well and put some thought into it then that could be a really nice project. You could lose the background all together. What about having a train track that's going thru a really simple white space and then do your florusack animation there? it doesnt have to be in a desert does it?

Or you could just have the desert and do some nice slow fly thru's of your environment. I feel that either of those ideas will attract a better mark than your full blown story, simply because of your lack of experience.

Sorry if this sounds a little negative, I hope you see where I'm coming from and that it makes some sense to you.

Alan