In Gillispie County (the county for Freidricksburg), for tracts in the 101 to 250 acre range, you are looking at an average price per acre north of $11,300 per acre. So, the 160 acres will be around $1.8 million plus the value of the improvements.
With a 2500 sq. foot house, figure roughly $2.3 million for a nothing special house, ok fencing, an old small barn, and relatively rough land. If you can find it.
For land with live water, expect to pay more, if not considerably more.
And, you will be potentially bidding against developer types who will carve up that 160 acres into 5 to 8 smaller tracts, add utilities, build drive ways, and sell the land for more per acre to retirees who want to build their dream home in the Hill Country.
Bigger tracts (over 100 acre) have seen some of the more rapid increrases in per acre prices. One, because there are relatively few of them, and two, because they can be cut up. Further, bunch of regular folks are trying to buy bigger tracts in order to simply hold the land (very low holding costs), and then give themselves the option of selling portions of the property later.
Having been in this market very recently, I'd suggest, cash is king. I'd also suggest, get as much of the mineral rights as possible. Ideally 100%.
In Texas, the minerals are the dominant estate, and the owner of the minerals can use the surface as reasonably neccessary to develope the minerals. So, if you don't own the minerals, they can put a well site/pad in the middle of your pasture, cut a road to the pad, and have a basically a large "generator" running out there basically around the clock for years.
Also, you will want all the water rights and all the wind rights.