That's a big, but very cool, project you're undertaking. Seeing the pics of that tall double-decker behind a tow truck was pretty impressive. Since you can't post photos here until you have 5 posts (or so?), I've taken the liberty of snagging one of your Instagram pics to put here for others to see.
As you mentioned on IG, that Detroit 2-stroke engine will outlast you and all of us. I started up one that sat in a salvage yard for 9+ years and drove it home, from Idaho to AZ. But...and this is very important...if they have sat for a long time, it's very common for one or more injectors to stick open. If you try to start it without correcting that, the engine can run away and destroy itself. The process to check and correct that, before you start it, is pretty simple - but please reach out to one of us who work on those engines. Feel free to call me...nine two eight, 554-5219. Or reach out to Mike, who goes by Crown_Guy here. There are others here, too.
Here's your bus pic - very cool!