Anyone use this to fill in a large area? Like a 250 sq ft small fenced area around a deck? Like a grass free yard? I'd like to plant short grd cover.

Yes, the QUIKRETE® Walk Maker® Building Form can be used for a large area. The nominal dimensions of the QUIKRETE® Walk Maker® Building Form is 2 feet by 2 feet by 2 inches thick. It is intended to be used over compacted stone/sand/dirt. For better results, it is recommended to remove at least the top 1 inch of the top soil and level the QUIKRETE® Walk Maker® before filling the mold with concrete. View instructions online at https://www.quikrete.com/athome/walkmaker.asp. The joints between the “pavers” can be filled with QUIKRETE® Mortar Mix Type N (No. 1102), QUIKRETE® Mason Mix Type S (No. 1136), or QUIKRETE® Sand/Topping Mix (No. 1103). Avoid getting the any of these materials on the top surface of the patio. Make sure to remove any material that does get on the surface of the patios to prevent discoloration. It will leave haze if not immediately removed.