Ah yes, the 305 Dream...when I was a kid I called them a "nightmare". Now I think they are just plain cool. I wish I would have kept the last one I had.
Great score for $100.00.
Does the engine turn?
The petcock assembly is an odd rubber / cork type seal set up and will need rebuilt. Kits are pretty cheap and simple to install.
Carb rebuild is also easy.
If the engine was still in running order, the fuel system attention should get things going again.
The old 305's are pretty bullet proof.
I've taken a blank Honda key...applied firm pressure to the key in the switch and that left a little "mark" on the key blank where it contacted the tumblers...then carefully filed at the "marked" areas. Finally had a working key after wrecking one key blank. I had to wiggle the key a bit to get the switch to turn but it worked....or simply pay a locksmith to make you one.
PS - Looks like your dog is "alerting" on the muffler...probably a rodent in there..lol