Prouboy,  I judge by the consistency of the dough, and you do want it pretty dry to work with successfully.  If it is too sticky you can also make a bed of bisquick or flour to work on and sprinkle more on top as you pat it out flat.  You need to remember to bring some extra flour on the trip for this necessity, or remember to hold some back from your recipie when you're making them.  In all instances the bisquick dough is not as easy to work with as yeast dough; just dumping the whole ragged mess into a greased pan would work anyway, just look a bit weird.   ;D
When I make them I work on a large plastic zip-lock.  To roll up you can use the bag to support the dough, rather than trying to directly pick up the dough.  Pinch the edge shut along the roll, cut them with a string by sliding string under the roll, bring the sting ends together over top and cross/pull to cut through the dough without squishing it.
Regarding pans, I use an inexpensive lightweight aluminum pan.  These are easy to find at a dollar store or goodwill.  Foil pans will work too, but are pretty soft and need a little extra care and support when moving them around full and/or hot.  I find that your cooking helpers might not remember this and it is a bummer to have the brownies on the ground  :'(