That is a lot of music, however, in order to win that MTNA competition you spoke of, that would be the kind of program you would have to play!
I'm doing that competition as well, but my state level is held in mid-Novemeber 2006. I'm playing a similar program as you - a Bach partita (only no.3 instead), a Beethoven sonata (op. 90), Book 1 of the Debussy preludes, Ravel's Ondine and either the Tchaik no.1 or the Rach no.2.
Actually, I played this year as well, but it was the first year I was eligible, I played the above program, but I was nowhere near ready with the Bach and Beethoven and ended up getting 2nd at State (sigh...).
So like you, I'll be spending most of this year preparing my program. This is what I would suggest for a practice schedule:
Don't work on every piece every day. Sometimes, I find that skipping a piece a day gives my mind some time to "refresh" on it and give it a different outlook. Also, some of your pieces will require more work than others (like you don't already know that), such as your Rachmaninoff and your Ravel. Also, try to spend more time on the passages in the music that you have problems with - and above all try and learn the music right from the start. Of course, I can't stress how important the learning the proper fingerings are.
A lot of this seems like common sense, but in a way I think that practicing should be like common sense - powerful, but not complicated.
It is comforting to know, that you won't have to play all of that music, either. Unfortunately, you don't you what they'll pick. But you can play on predictability of course: for example, I prepared the whole book 1 of the preludes this year, but I knew they would only make me play about the first 5 or so- esp since I choose it as my starting piece. It's good to play 'sets' like this, because they impress the judges and you won't have to play them all. So yeah, they will probably only hear the first half of the Paganini Rhapsody (not that you shouldn't prepare the 2nd half! You never know.).