suavojr, just like DesirousOfChange said, your history of juggling being an MS with pioneering gives you any easy out. Plus you have months to prepare. Perhaps you might go back to the brother who just gave you the "heads-up" in short order and start prepping him for the fact that you don't want to be considered this time around.
"Brother Heads-up, I've been thinking and praying a lot about what we talked about. I've been working very hard for a long time, so much so that it's really begun taken its toll. The more I've thought about it lately--even before you talked to me-- the more I had actually been thinking about dialing it back a bit. So although I appreciate your kind words about the next CO's visit, I have to admit, I could almost feel the added weight on my shoulders just thinking about it. I just feel like if I keep going like this, I might just burn out, never mind adding additional responsibilities. I know that an elder needs to to give 100%, and I'm not in a place right now where I can do that after ensuring me and my household are spiritually strong. I hope your not disappointed in hearing this. I just don't want you and the CO to be disappointed if, when the time comes, I don't feel up to accepting assignment."
If you're bold enough, you can even use that conversation to bring up that you'd like to ask for a reduced load when it comes to meeting parts and/or MS responsibilities.