Training for function, not just fitness.
I once asked what fly works best on a river. "Simple, pick the one you like the most. You'll cast it more, stay out longer, and naturally put yourself in better spots to catch fish." Training works the same way. There's no perfect program, just the one you'll actually do. If you like it, you'll stick with it. And that consistency is what moves things forward.
For me, training is more about what gets me outside — biking, running, hiking, skiing — and what keeps me outside through weight training and yoga. Being outside is key for me. When I am outside I am reminded of the splendor of the created world, I feel like I can breathe, and mentally I am clear-headed.
At the end of the day, you have to move. The body was designed for it, and when it doesn't, things start to break down. With MS, you just feel it more. So it becomes really important to keep finding ways to stay engaged.