I can't get the fittings loose. I just keep rounding the bolt.

 

You will need to split the nut, they are designed to turn so that you can hold one end and turn the other.
I have to split the nuts on the fuel filter with a hack saw and then pry them off the first time I changed mine.
Now I change it once a year and use never seize on the threads to avoid this problem.
$10 and 30 min once a year it totally worth it to me to save this mega hassle.

 

I was able to get it loose. The rover runs smoother now. Small task but a huge victory for me.