I don't climb there a ton and don't recall how much gear is available, but my first thought was something at Bunkbed wall. The description here for Gimme Three Steps mentions it is a good first lead: https://www.mountainproject.com/route/105897715/gimme-three-steps
Gimme Three Steps or Baby Steps. GTS probably has better gear. There's also those easy short lines in the bullwheel section of the D. Barre cliff. Also maybe take a look at app route 71, "Scramble Corner".
Bring a short rope if you have one...most of the routes in Peterskill other than Dickie Barre are shorter than most gym routes...I have a 70m I cut in half for using in the gym and have used the 35m half to set up topropes there. Since most of the routes are walk-off you can easily lead on a short rope. Breakfast Wall (the section closest to the parking lot on your right) has Over Easy (5.3) a very easy arete, and Cornflakes (5.4) which is also quite easy and short.