Well it's part training and part challenge to be honest. I have 2 big holidays/treks next year that I need to be fitter for (less fat, more strength, more hills). I wanted to do both for a while, the last 2 years, but I just haven't been fit enough. The last challenge was meant to get me fit for this year... that ended well! :-)
I might as well put it out there what I want to do next year. Everest base camp in March and the John Muir Trail in September. Both very big and very challenging for a fat lump like me. So far this year (Since March) I've lost 15Kgs, which is probably more than I have ever lost before, so I'm on the right track. I probably need to lose another 35Kgs to do Everest base camp (along with getting 'hill fit) and another 10 on that for the JMT (along with lots more hills and learning to how to poo in the woods...). Those are guidelines, I might be fatter but fitter in the end, but I'm happy to guess those figures for now.
I can afford it (or will have saved enough for both) and my planned dates for the treks fall nicely with my shifts, so I have the leave to do it. All that I need to do is in my control.
Everest Base camp will be a big challenge in just over 9 months. Opinions of fitness range from 'reasonably fit adult' to someone who can do the PYG track in 2 hours 15 mins carrying 10kgs. So if nothing else, I'll have to get out in the hills a lot more. Starting next week along the Norfolk coast....