Check out Sharon Schambers videos on youtube. A card table beside my dining room table and I can do any size up to 94" wide. My boards are only 8 feet long. White prefinished 1X4s from Home Depot. Smooth as can be and just pinned - no basting. My only precaution for you is not stretch the batting - just pat it in place.
I have used duct tape with no problem on quilts, but never tried on carpet. I know I'd pin the quilt to the carpet.