HI Frosty -
If you'd like, PM me with your Email and I will send you the trail description laid out on a spreadsheet with all the mileage points - It may help you with your planning.
Piseco has a small general store just after you cross Rte 8, on the right - It has basic general store and camper supplies, but not a lot of backpacker supplies - There are no other places for supplies for at least 3 some odd miles until you get to Cascade Pond (or alternatively Lake Durant Campground and take the highway)and peel off to Blue Mountain Village, or Long Lake Village.
From the highway crossing at Piseco, Continuing up towards Piseco Proper, you will pass the airfield and then the post office on your right.
Once you get to LLV, turn Right (N) on Rte 30 and go about 1/2 mile and the PO is on the Right (IIRC). LLV has a laundrymat on the right before you get to town and Hoss's has some supplies. There is also a Big "M" grocery store by the post office, though it might be under a different name now.
The times I did it, I was glad I mailed my stuff, (I tend to dry a lot of my own veggies and stuff) From my experience, The backpacking food at the smaller stores was more "ramen'esque" than anything else, 'course you might find some good items. There is also something nice about pulling into a post office and getting your bump box, taken what you need, leaving what you don;t need and sending it onward.
Cheers
Rick