(Sorry, guilty of posting multiple threads - same topic as my phone was having issues and I didn't think it went through)
Discovered there are actually two answers to this!
1) It takes roughly a full minute to bleed out the air from the line (front of coach to almost the rear.
2) (More importantly & NOT covered in the manual!) You have to PUSH IN AND HOLD on the stove top nobs to get them to actually open! Just "turning and releasing them" will NOT allow LP to flow! (My DW happened to casually mention this...after I farted around, frustrated with this for pretty much 4 hours on Sat!