I tried the iron seam tape to repair a pair of pants and it didn't hold very long. I also used seam glue from Michael's (sorry, I don't remember the name). It held on a small zipper repair but did not hold a name patch on a waterproof jacket. I think the fabric makes a big difference.
My wife made covers for the Campster
out of sheets with straps and Velcro to hold them in place. Some sewing was involved, but not like you would need to replacement cushion covers. She did matching curtains as well.