Learning Bach to play Beethoven

I'm back on a piano playing kick. The urge has taken me and I feel the need to do something productive, but non work related. So I've dusted off the ivories and am trying to get a good half hour to an hour's practice in a day.
My long term goal is, as it has been for the past decade, to play the entirety of Beethoven's Moonlight sonata. It's been some years now that I've been able to play the first two movements passably to well (depending on time of day, phase of the move, and state of my motor neurons). But the third movement is this:

Technically, it's a very different beast to the previous two. Rapid finger movements in both the right and left hands, and essentially a style that is more baroque (and reminiscent of the harpsichord) then the other two movements. From a simple physical performance stand point, my hands cannot yet handle that sort of athleticism.
A few years later my mother sent me some pieces to practice that her piano teacher had recommended for me. One was a book of basic exercises I was familiar with, and hated. The other was Bach prelude #2 in C minor from his Well Tempered Clavier series, which is a series of preludes and  fugues written, in part, as exercises for the harpsichord. Unlike the other book of exercises however, these pieces are actually fun and pretty on their own.

So I'm putting aside the Beethoven, and focusing on this prelude (at quarter tempo, let's be honest). And while my aim is to be able to play the whole prelude, I'm also using it as a learning tool. I'm focusing on my finger work, and practicing my sight reading (which is terrible). I'm working on strengthening the little finger on my left hand, and making my movements quick and precise. These are all skills that will be vital for eventually tackling the 3rd movement of the Moonlight, but I'm working on them in a context that brings more immediate rewards.
In many ways, much of what I'm doing as a postdoc (though not all), is playing Bach. I'm funded out of my PIs R01 for now, so that means I didn't design this project. And my long term goals (by definition, as a postdoc is a training position of determinate length), are not going to be realised here. So much of what I am doing here is learning skills that I will need to fulfill my long term goals. Yet, on the other hand, I am also doing something that is important and interesting in and of itself in the science I am doing here. If that were not the case I would be as bored and resentful as I was playing scales on the violin. Finding the balance here, between learning what is needed for the future, and doing what is needed for the project now, is key.
Ultimately, I will move on from the Bach when I feel there is nothing more for me to learn from it, and I will tackle what I planned. But I will enjoy learning to play Bach (and who knows, maybe I'll take another detour, and another). And ultimately, I will move on from this postdoc and do my own, other thing. But I will enjoy doing this science while I learn.