I'll share my insight with you, as I did both after graduating with a degree in kinesiology and intending on going back to school for PT. Both situations have their benefits and negative opportunity costs. Ultimately though, as someone else mentioned, your direct PT observation or work experience will be more important than either of these situations. As a chiropractic assistant, you will get the patient management skills and experience that you can talk about, but with Chiropractics working outside of the traditional medical model, your time their won't mean as much to the schools as it does to you. A couple things about training. First, if you intend on going back to school in a year, realize that your first several months of training will be just building a client base. That's just the nature of the business. You don't show up and start making real money out the gate, especially without any experience. So if you don't have that financial flexibility, forget it. The tradeoff is that you make your own schedule. So presumably you could get a ton of observation hours to offset it. That flexibility could also lead to getting a PRN (as needed) rehab tech job that demands that type of flexibility to fill in as needed. That's how I got my tech job while I was training. The other benefit to training is being in a field that will require you to stay fresh on your anatomy and physiology. But again, schools aren't going to put a lot of emphasis on your training experience, but it is a decent means to an end with the flexibility it allows for other PT related pursuits.
I also left school thinking I would only take a year off. What you don't realize is how early you have to start on the process. Many schools applications are due in early fall. So to be ready, you have to be on top of your essays, observation hours, GRE, any additional pre-reqs. Don't get caught by short-handed on time and get educated early on what your timeline is like for all of your schools.
That's my two cents anyhow. Good luck with your planning. Let me know if you have anymore questions.