You better like training
This one is is the foundation. You have to want to train. You have to want to spends hours on the trail. Oftentimes they are by yourself for hours. And then there are the group runs. If you don't like the group, then it's great that you can run alone and vice versa. Either way you have to love being out there. As a musician, you have to want to be in the practice room. I started my music education as pianist. Practicing the piano is a very lonely endeavor and as a fairly social person I found myself very unhappy with the practice room by the time I hit college. In defiance, instead of majoring in piano, I chose to major in voice. (Big rebellion there, I know.) Although I had to practice on my own for several hours a week, I discovered the joy of rehearsing with others, whether it was in the choir, a show, or with my pianist. All of sudden, all that solitary practice led to rehearsal with other people which meant such joy for me! I found my desire to train again!
I had a former student that told me when her mother said it was time to go to rehearsal she always would shout "Whoohoo!!!! Rehearsal!!!!" If you can't shout "Whoohoo! Rehearsal!" or "WhooHoo! Training!" the majority of the time, then it might be a good idea to find a different activity.
Enjoy the journey
100 miles is really long! So are performance schedules where you perform 7 days a week with a total of 8 performances. (That's the Broadway schedule.) Or, 5-6 performances per week with rehearsals during the day for the next show. (That's more of the opera schedule.) That would be like running four hours everyday and 8 on Saturdays.You better enjoy as much of the journey as you can because you're going to be there a while. Which brings me to:
Is your pace sustainable?
You've done the training, you've arrived at the race. You then have to ask yourself the following questions. Did you over train or are you ready? Do you need to start out slowly or is a faster pace going to be better? Or in the case of a singer, did you practice enough or too much? Can you sustain the length of the show? Is your throat too tired or are you in good shape? Have you taken on too many performances with rehearsals on top of them? Do you have time for family and friends? for yourself? Can you make it to the end of the race? Where is the "end" of the race for you....? Can you sustain the pace?
Recovery is 30% of training
Recovery, rest, sleep, eating correctly, saying "no" to going out when you really need to stay in. These are all extremely important to both the athlete and musician. And I would go one further with singers: no talking when you are not singing. Those muscles need rest. And my favorite: It's OK to take a nap!
You are only as good as your crew and support team
A missed water bottle, no fuel, clothing isn't available, a pacer who doesn't know you and your mental bandwidth, you spouse/partner is less than supportive... the list can go on. These things are crucial to a successful race. In a singing career, you may do 100 auditions in a year and only get one callback. You better have your support system in place to sustain you through the long haul. Those loving and encouraging words at the end of the day (or at the aid station) are what's going to keep you motivated to stay in the race or even to continue to train!
It's ok to be mid-pack as long as you know that you have done your absolute best.
I think this is the single most important item on this list. It has taken me almost my whole life to be "OK" with being a "mid-pack" singer. That always sounds so bad to me. But let's think about the picture of the ultrarunning community and the professional singer community. How many people actually run ultras in comparison to the world population? It's a very small percentage. And how many people actually sing the big vocal repertoire and perform it fairly regularly? Again, not very many in comparison to the world population. As ultrarunners and singers, we get to do something that most people never get to think about, let alone attempt! The fact that as runners you get to see and experience places that most people only dream about is truly exceptional. And as singers, we experience the emotions and exquisite beauty that is only found in what we do. It doesn't matter if the level of running or singing is only midway from the head of the pack, that is still way beyond what most people only dream about. In the end, you have to run your own race and everyone else's times and opinions be damned!
So in the spirit of the ultra psyche, here is a bit of my "ultra running"...I mean singing....