You can buy your licence on line or locate a local agent here.
http://www.vtfishandwildlife.com/buylicense.cfm
Further, I can't help you with local ponds in VT as I have yet to wet a line in the state of VT myself, but if I were planning a trip I would look into dam regulated waters such as the Lamoile (Not in the valley but not too far and reportedly nice fishing). Streams with dams are generally less sensitive to precip than unregulated waters, and unless the precip is heavy and sustained enough to cause a dam release the water might not rise much if at all.
Check:
http://www.americanwhitewater.org/ for flow data
And since your on the Cape. Have you ever walked out on the Brewster Flats during the falling tide fishing for stripers? It's a nice take for any fly fishing or light tackle enthusiast.
Good luck.
Good luck.