The RIDER Act would expand federal disaster relief eligibility in two main ways. First, it allows areas that border a federally declared disaster zone to receive the same federal assistance even if they weren't directly declared disaster areas themselves, provided those neighboring areas are under state, local, or tribal jurisdiction. Second, the bill redefines what qualifies as a major disaster to include cumulative damage from multiple natural disasters that occur within a 12-month period, allowing federal aid even when each individual event wouldn't normally qualify on its own. The Federal Emergency Management Agency must issue interim guidance within 60 days of enactment and develop final rules within 18 months to implement these changes. This legislation affects communities in disaster-prone regions and how federal disaster assistance is distributed following natural catastrophes.