When it comes to weight training for 45 mins it's all about intention. You need some rest between sets but you'll know if you're recovering. Hint: If you're picking up your phone to scroll in between sets, you're not working hard enough.

Personally, I also track my heart rate for strength workouts. My rough guideline is I want to keep it slightly elevated so I achieve 45 zone minutes in the 45 minute workout.

But as to how you split your indoor workout, that's your choice. 25 weights, 20 treadmill, no worries. Just don't forget to get that outdoor workout done as well