You'll have to let us know how that holds up over time, just out of curiosity on my part. I've never tried the spray can bedliner but I have done several Raptor Liner jobs and have been very happy with that.
As for your carpet question: I take used carpet to the car wash and use their hot soapy water followed by the normal cold water rinse. That's as good as anything I've found and way easier than trying to do it at home. For stains it kind of depends - pretty hard to beat laundry detergent for most stains... dilute it with water and work it in with a brush, suck it out with a carpet shampoo machine. Oil & grease can be removed with Simple Green, dish soap, chlorinated brake cleaner. Iron-Out works pretty well for rust stains. Sometimes they are just stubborn and won't come out but I have cleaned some really nasty carpets this way and they almost always come out good enough.
The roof & hood paint: $800 seems like a very fair price for a body shop to paint those. I see at least a day worth of work there. I'd be shocked if most body shops charge less than $100/hour these days. You can definitely do it yourself for a lot less but you'll have time and materials into it - if you use professional products, guessing $2-300 worth of paint, primers, sealer, some other chemicals plus sand paper, masking materials, etc. I think you could make it look OK with Rustoleum type paint but the color will for sure not match... black accents/stripes/etc or something might make it a lot less obvious. That said if it's an otherwise nice truck, do it the right way.
