Welcome to the Forum. That looks like quite a project, but you seem up to the task. At least it sounds promising when you crank it. Fresh fuel is a good start, also it won't hurt to give the MAF a cleaning. Have you checked it for DTC codes?
With the rear window split, you should probably make sure that the Central Locking Unit under the driver's seat has not been exposed to moisture. If you get to it before any major corrosion sets in, a good/careful cleaning can preserve it.
I have bought about a dozen cars from insurance/salvage auctions, three of them Boxsters. I have sold or traded all of the other cars and kept the Boxsters. Once you get it sorted out, it may be hard to part with.
