I'm not breastfeeeding any more as mt daughter weaned herself, but when I was breastfeeding, I would just feed anywhere. I would feed sitting on a chair in the middle of the shopping centre, in the chemist, walking through the supermarket, in the library, waiting in line at the bank or post office... and I never bothered to cover up either. I did it discreetly and I dont have big breasts, and if people dont like seeing a baby being breastfed, they dont have to look. I remember being in Target when Claire was about 2 weeks old and my MIL was with me, she kept trying to get me to cover myself with a muslin wrap, and I kept taking it off because I didnt want to hide under the wrap.
I never really got any nasty comments. People would look as they walked past, other mums would smile sometimes. One mum walked past and said 'good on you' or something to that effect.
At my local (Very small) shopping centre, the parent room is so pathetic. There is barely enough room to even sit down in there. I used the room one to change a nappy, but never again because it was really bad. The big shopping centre near me has 2 biggish parent rooms which I have used before but they are in inconvenient locations so I dont use them much unless Claire has a really nasty nappy to change.