I got a '75 safari this last weekend. It seems solid, no obvious water leaks or floor rot. I am now in the holy s***! what do I do now part.

I went through it for about 2 hours before I bought it and missed a lot of stuff from excitement and ignorance. I tested the water system, more or less, and ran the fridge, burners and furnace before purchase. Now, in the calm aftermath I am going through a little more thoroughly. Most likely the fridge and water heater and furnace will need replacing. How hard is it to adhere to replacing with as close to original as possible? Should it matter or just get something that is current? This has not been altered too much as far as I can see, and I want to maintain that integrity. My wife, wants to rip out the faux woodtone and paint, but that will be another story.
I know I need the gas inspected, I can smell it with the tanks open and no appliances on(faint) . The city water line, I noticed tonight was disconnected in the back where it comes in and the pipe capped, hmmmm, must have been a problem there. Do I need to rip the floor up to redo water, gas, electric first?
All in all, I am pretty excited to have an airstream

and want to be a good steward of it while it is in my possession.
Is it important to go to an airstreanm dealer or can you trust an rv shop (dont have any relationships with any as this is my first trailer)?
I am getting the wheels serviced by a good trailer shop who is putting a round plug on my p/u to match the trailer. Or are those round plugs old and out of date? I have a 7 flat plug on my p/u now and was going to have them add the round next to it, as well as add a brake control.
Enough for one post. Thanks.