Sad that it escaped or was dumped, but cool you found it. I agree with the others, QT the snake in another room as you have no idea how long it's been out and about. It might even be worth a Rep-vet visit just to gauge the overall health of it. How was the snakes behavior when you picked it up?

Your caging will end up being different, but if in fact it's a male a Boaphile 421D would be a great enclosure.

I'm slightly jealous as I want a boa pretty bad. Good luck.