Anna, lots of variables here but we like to use 100 as a goal for big expeditions like a Denali for instance. Here are some thoughts from the UA website that Scott wrote:
Here at Uphill Athlete we have hundreds if not thousands of TSS data points. While trends are visible, the accuracy of our predictive model—predicting fitness levels for objectives—is probably below 75 percent. Having coached many dozens of athletes over many years, I am able to say that 100 is pretty much the price of admission for an O2-assisted ascent of an 8,000-meter peak. And those with a CTL of 40–50 are not ready for big mountain adventures. But whether you need 120 or 130 for success on Everest, I can’t say with much certainty.
As we accumulate more data and experience, we hope to improve our predictive model. However, there are some big hurdles we may never overcome in terms of developing a more accurate predictive tool, namely our reliance on hrTSS, the least accurate way of calculating the overall stress of training. When you layer on the fudge factors, our TSS numbers need to be taken with a big grain of salt. They are rough estimates and only work when comparing apples to apples. They are an imperfect solution—and also the best possible one.
I think speaking for something like Ecuador ideally you would have a CTL of 75-80 minimum. The reality is that you’re going to prepare as thoroughly as possible given your time constraints and recovery ability. A couple of additional thoughts, for expedition type mountaineering I think it’s just as important to have your CTL fairly high for a period of time (I.e. Hovering 85-90 for 6-8 weeks) than to have it hit 100 for a single weekend.
The other thing that is vital to this discussion is that you’re using hrTSS and adjustment factors so we’re comparing apples to apples.
Hope that helps!