Ponchos are tried and true, but they are not loved by everybody.
Look at a rain SKIRT (easily made at home) this is my preferred set-up The pants on the DriDucks are sorta lame and tear easily. But, they are very easy to convert to a rain SKIRT. Very efficient and easy to hike with.
Pack covers are a personal pet peeve. They are heavy, they leak, and they are NOT a multi use item. Use a 2.2 oz plastic trash COMPACTOR bag from your grocery store. THese are perfect. Use them as a pack LINER. They are multi use because you cha carry stuff around in the bag.
I have had mixed results with rain CHAPS. I just find 'em a little awkward to get on and off, and thus, I tend to avoid them.
I would suggest.
1) DRI-ducks suit
2) Rain Skirt made from the DRI-ducks pants
3) trash COMPACTOR bag as pack liner
Will dry ducks last a month on the trail? THey will if you are carful! Be VERY gentle if you have to walk off trial in the woods or bushes!
THey repair beautifully with - of all things - MASKING TAPE! Really, patched some tears years ago, and the masking tape has held up amazingly well! A little eon the inside, and a little on the outside, Cut the corners so the patch is rounded.
Take something for your hands. Super thin liner gloves (under 1 oz) are fine for the summer.
I am 6'1" and 165 pounds, and I use the largest size - and it's ENORMOUS. I like that. I can tuck my hands up in the sleeves, and plenty of room to add layers underneath.