This is a very easy DIY project at home depot or lowes. Just go buy how ever many feet of 10-3 SOOW or SJOOW bulk power cord you want, which they have in the electrical section of the store. It will cost you about $1.50 per foot. 10-3 means three conductors - hot, neutral and ground, in 10 gauge, which is what you need to support a 30 amp circuit. SOOW means heavy duty rubberized power cord, oil and water resistant, rated for 600 volts. SJOOW is the same thing but rated for 300 volts.
At home depot bulk wire is on a big rotating rack in the electrical aisle. They all stock exactly what you need and will cut to the exact length you want at no charge.
Then have them show you where the 30 amp plugs and sockets are, and buy two that match what you need to plug into. You can bring a picture or drawing of what the connectors you are plugging into look like.
To attach the plugs to the cord, you need a wire cutter / stripper (a scissors or razor knife will do in a pinch) and a philips screwdriver. Simply strip of about two inches off of the outer cable jacket to expose the conductors, then strip about 1/2 inch on each conductor, and then follow the directions and pictures on each plus and screw the wires onto the hot, neutral and ground terminals on each of the two connectors you purchased. Last step is to tighten down the cable clamps built into the connectors, and you are finished.
Only wierdness in this could be if you need a 30 amp RV socket on one end of your cable, which I can imagine they might not have at home depot / lowes. If this is the case, I would buy a short adapter at Walmart or camping workld that will convert the RV plug from your AS into a standard 30 amp circular plug.
Wiring this all up is about a 10 minute. Difficulty is about 2 out of 10.