SHOREHAM — While Vermont Gas Systems Inc. is now actively seeking the necessary permits and easements it needs to extend its pipeline south into Vergennes and Middlebury by next year, the company is also starting to lay the groundwork for the second phase of its expansion plans: Service to International Paper Co. in Ticonderoga, N.Y., by 2015, a construction project that will affect several property owners in Cornwall and Shoreham.