Mount Diablo State Park has trailer-friendly campgrounds with sweeping views and established parking pads that accommodate larger rigs, making it a reliable base when staying near Lafayette. Lake Del Valle at Del Valle Regional Park provides lakeside campsites and larger parking pads suitable for many towables, plus boat launches and restrooms. Both parks offer scenic settings, hiking access, and enough space to unhitch and enjoy day trips without moving the trailer. Check each park's size limits and reservation rules before arriving to ensure your rig fits the available sites.