In general the current legal climate surrounding environmental issues makes track building a very hard sell to banks.
I've done most things in my life in kind of a sideways legal fashion. If it was my task to build a track. I'd buy about 200-300 acres...I'd build a very small house somewhere on the back third of the property...I'd build a VERY long, wide, nice....scenic circular drive up to the house and back to the road. Not a freakin thing could be done to stop you in most places.
Now....you have a piece of property, you have a piece of pavement. You can legal invite friends over and race around your driveway as long as the neighbors don't complain and your friends don't sue. So....now you have a piece of property, with pavement, with bikes on it.
Assuming you built in the right locations...meaning in the middle of nowhere.....you attempt to sell the property to a non-profit motorcycle club for private use. Now you have a non-residential piece of property, with pavement, with bikes on it.
After a year or so of having bikes hanging out, playing around, you approach whomever passes for city fathers in that area about opening up the track to rentals, club events, etc. Discuss noise, traffic whatever. If the initial location research was done properly you should be able to pull it off.
The key is starting as a private owner, with a residence, the laws are mega more flexible where private residential property is concerned. Once that pavement is down...you most of the way there. Worse case scenario the club has sell the property, and hopefully take only a 20-30% loss.
My friends that do volume paving have told me that standard 3 -4" thick pavement can be done for about $2 a square foot including bed prep...assuming suitable land....meaning no blasting, bridges, huge earth moving projects etc....just bulldozing and gravel bed.
That's about $211 k per 20' wide mile. So figure min. $400-450k for two miles of pavement. Now this would be typical standard asphalt...like we race on at Frontier Land...just parking lot/driveway asphalt...I'm sure specialty paving would be a lot more. Realistically you'd probably want to spend more like $600k to make sure you have a rock solid base to prevent cracking or other issues for the first five years.
I still say 300 dedicated people could do it no problem. Total cost might be $3-4000 per person when it was all done. Each person with a percentage stake in the track. You'd probably have to generate $50k a year to pay taxes, insurance and upkeep.
Out of the 300 members...you'd hopefully have the resources of small earth moving equipment, mowers, logging, plumbers, electricians and carpenters.
I have no doubt in my mind it could be done in the midwest somewhere...OK, Mont, Wyo, etc....but then you'd probably not have enough customers to keep it afloat.
We have a local Harley "club" here that owns a couple of hundred acres, huge club house, has giant parties and swap meets etc. Been there for years.