My thoughts on the transporter (also beyond psyched that you're making it):
Both ends of the transporter (2x2 or maybe even 3x3) platform need power, a button on the platform dematerializes anything or anyone on the platform and saves it to a buffer. A second button materializes anything currently in the buffer, in a way similar to a trade beacon, so it will prefer to spawn on the platform, but if there's more than 4 tiles worth in there it will just scatter everything nearby.
The build materials should me mid to late tier, a little bit of gold and a bunch of plasteel, but perhaps make it possible to minify the platform, so that it can be brought to a new settlement in one go.
The platform should have a moderate power requirement in standby mode, and any act of materialisation or dematerialisation will instantly attempt to drain X amount from any connected batteries. If insufficient power is available, abort the action and show a message for that. Possibly add a trigger for increased chance of a Zzzt event when this occurs.
The transporter platform information panel should show the currently stored vs required power of any available materialisation or dematerialisation action.