So I just spent another 2.5 hours with tiled and ponytiled and finally got something to work with.
I actually spent only about 30 minutes with coding, the rest was figuring out how to get my map into corona...
This is probably the worst way of doing it, but now I have something to work with (player and some ground, both are physics objects)
I will spend some more time now to try my idea, I think its ok, as I only spent time on the asset, right? :)