Multi-tiered Goals

If I am honest, my Impossible goal is to write and star in my own action movie. I love action films and the thought of starring in one really lights me up. The issue is that the character that I want to play is 100 lbs lighter than I am currently. I know you always say that when we want to work on more than one area of our life (weight, money, business, etc), that we should focus on one first. I find that when I do separate out the goals my compelling isn’t as strong. For example, just writing the screenplay—why write this if I’m not fit enough to play this. Or losing the weight—this is so far away I don’t even have a script yet. So, in essence, using the lack of the other to negate whatever compelling reason I have to accomplish the feat. Having the whole thing (writing and getting in shape to play the role) seems like… a lot. So, what do you suggest? Break it down or go all in?