You should be able to backstroke the 400yd and do it in under 14 mins, it isn't a very fast pace.
My freestyle 400yd is about 10m30s and that actually sucks pretty bad.
For 500yd (T2/C2) you probably can't backstroke that one, at least not the whole way. And with my freestyle speed I can only do that in about 13m comfortably. A good swimmer, though, can probably comfortably do 500yd in ~8m or so. A lot of it is technique.
A couple beginner things to work on:
- Learning freestyle is mostly about learning how to breathe so that you don't get chlorine up your nose which just takes practice. Try going to the pool 3 times a week for a solid month, and if you put some solid time towards freestyle you'll get better at it.
- Keep your head down and try to keep your body horizontal (that one should sound familiar)
- Focus on pulling complete strokes -- extend your arms as far as you can in front of you and pull all the way back (either for backstroke or freestyle this will help improve your efficiency).
- I find that trying to kick harder gets minimal speed improvements but tires me out faster due to using the big leg muscles more, my arms work better for swimming than my legs -- you need to at least kick enough to stay fairly horizontal though. Of course if you're trying to get a workout and tire yourself out, kick as hard as you can...
And mostly the difference I see between the people in the slow lane and the medium lane is that the people in the slow lane keep their head out of the water, and have terrible trim in the water. You've got to get comfortable with your face in the water and get horizontal...