Hi Chris,
I don’t know your fitness history or age, which are two relevant factors I think, but I can share my experience.
I am 50 years old, with a deep endurance traning background, and relatively less specific strength traning background.
I’m also a father, work a stressfull job (high school teacher), and rarely train more then 5-6 hours a week during the “regular” semesters, but in the summer and vacation weeks I accumulate considerably more hours, especially when you factor in days in the mountains climbing, skiing, etc.
For me, following 5-6 hours of very light aerobic exercise combined with regular strength training has yielded great results, with much more endurance than I hoped or expected. I think that’s because strength traning has an endurance component, while the oppposite is not true (low intensity aerobic training has leff effect on strength).
I would reccomend sticking with the program. You did 2 months…why not do another 2 months? With a low volume such as this I expect changes to come slowly. I would also strongly advise doing strength traning of the uphill athlete kind, with a base phase, a general phase, slowly working toward a max phase, prioritizing strength without mass, and so on.
I strongly suspect that if you keep up the low intensity base and add strength you will start feeling more like you want to feel in the mountains.
Conversely, if you jump into the high intensity intervals and what not, I think you will see quick improvements and then a plateau or even a decline.
Good luck, and let us know how it develops!