and Welcome to the Forum!
Unfortunately, you're not likely to find much documentation for your coach. The best you can hope for is a chassis manual and individual documents for the coach appliances. Framing and wiring diagrams are simply going to be non-existent especially since Eldorado went out of business back in the 1990's.
Start finding the identification tags for all the appliances and systems, Furnace, fridge, water heater, etc. You should be able to find those service manuals online. This web site should get you started.
Service Documents and Manuals
Depending on what chassis you have under that coach you can probably find an Owner's or Service chassis manual online too.
Best of Luck!