1) what do you guys do for the PP and brisket I envision having full butts and briskets resting in the holding oven.
I use Cambro's and my smoker for hot holding. Unless you are buying a huge trailer space for a oven may be tight. Also ovens use a gas and electricity, gas expensive and electricity could be a lack of with ac units and hot water tanks etc.
2) How do you guys deal with ice and drinks? just a cooler, this is allowed here with proper handling. I do plan on having sweet tea and fresh squeezed lemonade that I will need to serve up.
I do canned soda's and bottled water and keep them in a cooler outside by the trailer and let people get their own from the cooler. With sweet tea and lemonade I would have to have more room in my trailer, buy cups, lids and straws along with make it. In a 7' x 16' trailer I don't have room
3) Do you use a point of sale system on board, sure make sense in my mind. If so what do you use?
I use a cash register that cost about $200 and does a great job.