Where to mount solar panels on roof?

Is there any factory wiring that you can leverage? I chose to place all of mine near the front of my TT. I did that thinking at some campsites you tend to back into shaded areas. That was good in theory but it probably didn't make much difference. The other factor for staying near the front for me was I could leverage a cabinet in the front bedroom to get my wiring to to the roof and it was close to the batteries. I mounted my controller in the front storage. As mentioned try to stay clear of vents and the AC as much as possible.