I do my cardio after my post workout meal. usually a 2 mile walk.
if you live in Alaska then yeah you probably want to get in your cardio at the gym but living where I live I like to take a walk on the beach or get outdoors.. the gym for me is just for weights and stretching..
I do like 5-10 minutes of Dynamic Warmups, do my workout, then stretch afterwards... I'm cutting back on cardio because I'm bulking now, but I'll do a 30 minute jog once a week, and high intensity speed and agility training once a week
There are lots of opinions on when a good time to do cardio is, and it probably comes to what works best for YOU. We are all different and what works great for one may not for another.
I personally don't like to do cardio and weights on the same day. I do cardio on days I don't lift. I eat and train for the goal that day. On weight days I eat big for muscle gain. On days I do cardio I eat lower cals and low carb for fat loss. That method has worked very very well for me.