[How much value does an IFNY lease with say 5 months left on it have? ]
That is totally dependent on who is looking at the lease. If it is someone with a rig available and a high interest in the lease then it could be a considerable sum. OTOH, if few are interested and rigs are tight, and the lessor hasn't indicated a willingness to renew a lease, it could be worth very little.
[The range evidently runs between 0 and $3,000/acre. Would midpoint be a fair guess? ]
The only way that any price even remotely close to the midpoint would ever be doable, IMO, is if it includes all of the existing assets as well. And even at that someone would be offering a premium.
Lets face it, production from this part of Erath hasn't been very good. Sure there is a well or two that look decent, but as a whole it hasn't worked the way that Stan and Co had envisioned. So, if they haven't already extended some of their key leases, if they haven't already secured a JV partner, then their best bet may be to just put the production up for sale to the highest bidder and move on down the road with whatever they have left. They aren't doing shareholders any service continuing the way they have been going. All JMO.