Like a qjet carb, the 2004r was designed by GM as a really adjustable platform for MANY applications. That said with the correct parts and a decent eye toward cleanliness a hack like me was able to get one together and functional. This isn't to say anyone can do it, but I feel if you have the where with all to drop one and put it back in, adjust the tv setup and do the research to get quality parts it can be done. That said, as above, things can and will go wrong with the clearest instructions and the easiest of tasks.
Is it easier to drop it off and hope for the best? Depends on how deep your pockets are and how much patience you posses. I'm pretty much diy to the core. I have talked on the phone, exchanged emails, texts and messages with pretty much every "guru" on this site and others who would respond. You do need some specialized tools and some detail oriented wrenching to make anything work on these, and we haven't even started on a converter yet.
Keep on keeping on if that is within your goals. Mr Husek was SUPER generous with his time with me on the phone and i will ALWAYS recommend him. Mr Janis was also very generous answering my messages so he gets a thumbs up too! TTYPE6 was also generous wit his time answering my questions and he isn't even in the transmission business.
I hope you are able to narrow down and solve your probs. But if not keep posting your questions and I'm sure someone will try to provide and answer.