A series of interconnectable foam-block ramps and platforms are provided that are cut from low density EPS foam but coated with durable exterior polyurea coating, and that include optional hard surfaces, and edge-and-corner treatments, and railing with hand grips. The components resist deformation and withstand extreme weather conditions, but are surprisingly lightweight and include integral hook connectors that securely engage. They can be easily assembled/installed to form a handicap ramp and/or arranged to form novel “terrains” for wheeled devices and/or arranged to form stages and platforms. The components are sufficiently durable to support high-stress wheeled devices such as a wheelchairs, trick bikes, skateboards, in-line skates and the like. A variety of optional components include a curb-simulating element, intersection-forming platforms, X-intersection connectors, double-decker platforms, steps, and railings.