Pacific Southwest Railway Museum is a 1 mile round trip walk/tour with 35 feet accumulated elevation gain. Located 37 miles east of National City California. December and January are the best months to enjoy this activity.
Take the backroad to Campo via SR94 that travels very close to the Mexican border. Explore the Pacific Southwest Railway Museum (closed weekdays). Is the Carizzo Gorge Railway still operating? Hard to tell given the light wear on the rails. Its a good reminder of "the impossible railway" that includes the Goat Canyon Trestle.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.