...He scoped out the bus and found out that our alternator is shot, so we now need to get a new one of those and a new regulator for the alternator. Got a price quoted at $75 to do that, so hopefully we can drum up that much soon.
That sounds like an amazing deal to get an alternator installed! You got lucky on that. With a 40 year old vehicle, you can expect frequent breakdowns until you have pretty much replaced every part that can possibly break. You might want to get a mechanic to go through the bus and give you a list of pre-emptive parts replacements you can prioritize based on cost. Especially those parts that bring the bus to a standstill in a possibly inconvenient time and place when they stop working.
This is the experience I've had with old vehicles. There are a couple years of frequent breakdowns and parts replacements, and then eventually it gets more reliable since I've pretty much replaced everything that is likely to malfunction.
You might try sending a private message or email from the forum. They may not have a reliable internet connection where they are, and are therefore not able to check this website often. If you send something that triggers an email perhaps they may get it on their phone.