Jon,
It would depend on exactly where the land is. In my town, property goes for around $3K an acre and if you put a $65K home on the property and your septic has been upgraded, it would sell for maybe $200K.
That same property in the town where I grew up which is around 20 miles north and all low lying swamp land, would go for $120- $150K. As far as farming value, not really. We have plenty of over grown pastures that can leased very cheaply. Actually, there would be more value leasing it for hunting purposes.
The reason you could rent it so cheaply is because most people who are willing to pay $700 + in rent, can go out and buy a cheap home for a lot less.
As an example, I bought my home which is a 3bd / 2 bath on 5 1/2 acres for $92k, 7 years ago. At the time, the area was the place to be due to our GM plant going full steam and it's near a main freeway. Not many renters see the value in living on 25 acres, so it would be much harder to rent, then let's say 1 acre and a house.
The house right next to me is a 4 bd / 2 bath on 10 acres and it's rented out for $450 a month. The renters are renters, they have no desire to farm the land or raise any kind of live stock, they just wanted to be in the country and have their kids go to a good school system.