First post and first trailer build

First of all thanks to all of you who post ideas and builds....I hope that I can return the knowledge someday.  I purchased a used trailer 6 months ago and have been re- working it whenever time allows.  My first question is with the gas line and regulator.  I have 3/4" pipe throughout and the 2 burner griddle, 2 burner grill and 4 burner stove all have regulators.  My 115,00 btu fryer has 3/4" pipe but no regulator.  The manufacturer said just to use a step down or 2 stage regulator at the tank.  All of the propane dealers in my area do not deal with this or do not want to.  My question is which 2 stage regulator do I need and what does that do to the other regulators.  Also....maybe  a dumb question but if the fryer is first in line, what keeps it from starving appliances down the line.  I will have a 100 lb tank and 3/4'' line from regulator...thanks in advance  Mike