Hi Michele.
Let’s work through a few of these things.
First off, are you comfortable now in understanding the different fuel systems used during exercise? Fat metabolism, muscle glycogen, and blood glucose? And how your body uses a different combination depending on the type of exercise you are doing?
I think that running first thing in the morning without a meal is not the easiest thing to do for any kind of hard workout. It is fine for easy stuff, where you are primary using fat.
But for more intense workouts, first thing in the morning if you have not eaten, your liver glycogen is somewhat depleted and you don’t have any carbs to work with. And on top of that, for some people their BG spikes when they first wake up. And they may not have time to get their BG settled before they start.
If you always wake up at a perfect number, sure it may be easy. But having a few hours to eat and get your BG settled seems to make it easier.
One time I tried a marathon without eating breakfast. I won’t ever do that again. It was horrible. Felt like I had nothing by mile 10. Never again.
I think 4 hours is really a good time frame for normal workouts. I do 2 hours for races.
Doing it at 4 hours means you have some food, you have replenished your liver glycogen, and you have no (or minimal) IOB, and you have had time to get your BG settled.
With Tresiba, your basal rate is fairly flat all the time, and you can’t adjust it.
Ideally, you don’t want to start above 150. If you are committed to using MDI and Tresiba, you may have to feed your basal (option 1) as you go along to keep from dropping. That is one way to manage BG, without starting at a higher number.
Alternatively, you could look at a different basal insulin that lets you adjust your basal for different times of the day, so you would have less basal during your run (option 2). I am a big fan of Levemir for athletes that want to stick with MDI.
And a third alternative would be looking at getting a pump, where you could turn your basal off prior to exercise (option 3).
Yep!
The post below has it detailed pretty well. I could go through them again, but this post has several reasons numbered out and with detail. So take a look at this thread. 
(Make note that there are reasons pertaining to health, but also reasons to performance…)