The answer may be as disappointing as it is obvious: Its by simply not getting out of shape over the winter in the first place.
As much as people don't want to hear that, there is a certain level of relief in this reality...if you don't backtrack in the first place, then you never have to catch back up later. Maintenance is EASY. Let me say that again: Maintaining an excellent physique is EASY. You don't have to be a personal trainer to look great, you don't have to exercise non-stop and you don't have to eat perfectly all of the time.
BUT you do have to get in shape ONCE in the first place so that you can simply switch your focus to the easy maintenance phase and just stay on that easy maintenance phase forever.
The fastest, simplest, easiest way to get there in the first place is to get a solid Dallas personal trainer who knows what they are doing, can get you results quickly, can help you speed up your metabolism so that its easy to maintain for years, and (most importantly) can teach you what you need to know and understand so that you can be empowered for years and years of successful maintenance of the physique you have created after years and years of only dreaming about it.
The whole thing sounds simple (and it is). Work with a professional Dallas person trainer for a while, get your results and gain knowledge and understanding, go back out on your own if you so choose, and then enjoy the body you have created for years and years to come...