"...large contractor grade trash bags..."
These bags or 'rubble sacks' as they are sometimes referred to are fantastic bits of kit with multiple uses, take a few
I'm presuming that you already own a Triangia cookset, if not you could save yourself a few bob by using a trade sized peach can or coffee tin instead.
The cheap and cheerful builders tarps mentioned earlier are well worth a try, however rather than use the eyelets (which are prone to being ripped out), tie a small object such as a stone or pine cone into the sheet corner instead.
I'm just debating to myself now whether to get a tarp or poncho....Oh, I'd need to buy some paracord too.
You can use your tarp as a poncho (although it helps is you possess a large brimmed hat too)
Any strong cord will do the job, don't get hung up on whether its paracord or not
As mentioned by 'DavidJT' earlier, a first aid kit should be on your packing list.
Have fun