Jennie, if I still lived in Vermont, I would take you up on your offer!
My impression of permies is that we are all just spread out too much, so the only practical way we can help each other is when a place to stay is included. And if we came all that way, it makes sense to stay a while.
I think the regional forums could function as you describe for more casual, daytime helping each other. Right now I guess Eastern USA would include New England. If you post there and mention each state you would be willing to help out in, people watching mentions of their home state would see it.
When I lived in Vermont, I used the Front Porch Forum for finding small jobs and people wanting help like what you describe in my
local community.