First, I hope you have or will test the walmart tent outside in the rain

yes, you can cut the bottom of your pad, if your feet get cold you can always shove extra clothing or your pack under you.

There was a recent thread about rolling vs. stuffing and as a sleeping bag stuffer, stuffing won. Don't waste time rolling it up to put it back in the stuff sack.

To make recommendations for clothing, you'll have to specify where you are going. You will want to bring enough for most possible conditions, including lots of rain - especially in N.E.

map, compass, first aid kit, some rope, headlamp/flashlight, water purifier (tablets, UV, pump or gravity kit), camera and small knife.