The New Paltz to Highland trolley (Nee: 1900
New Paltz and Poughkeepsie Traction then 1903
New Paltz, Highland and Poughkeepsie Traction) ran basically along New Paltz Rd from Hignland out to New Paltz. Crossed the NH at roughly Lloyd and again just west of Chodickee Lake Rd. Survived until circa 1925.
"The New Paltz and Poughkeepsie Traction Company is in operation from Highland on the Hudson to New Paltz in the Walkill Valley.
A track connection was made with this company's {NYNH&H} line at Pratt's Mills, which is about two miles back from the river, and a through car service inaugurated via the
great Poughkeepsie bridge, between New Paltz and the city of Poughkeepsie, and connecting there with the city electric lines. Easy, cheap and desirable route between the Hudson and Walkill valley." source:
http://www.catskillarchive.com/rrextra/pbhigh.Html
also see: Down to the River by Trolley: The History of the New Paltz-Highland Trolley Line (Paperback)
by Glendon L. Moffett (Author)
If what you saw was in between Lloyd and Chodickee Rd., IIRC that was the old NH alignment. N 41.73606 W 73.99099