Wear a 50lb Ruck. Ruck around DC for 14.5 hours (10pm - 12:30pm the next day). Log approximately over 20 miles. Make sure you stop and do plenty of low crawling any and everywhere (National Mall, rivers, creeks, and mud tunnels). Also for good measure throw in a couple hundred each of burpees, pushups, situps, flutter kicks, squats, and lunges.