Joining late, but my 88 K5 got 3 years ago originally with 6.2, banks turbo, 4" lift, corp 10s w/ 4.10s, 33" tires, 700r4, np208. With that setup I was still getting 22mpg and loved it to cruise around town and on the highway. Originally for me with 148,000 miles on the odo too.
If you can find one with either the Banks kit or a 6.5 turbo swap, do it. I've driven a few NA 6.2s (admittedly never owned one) and they're not....ideal. With the Banks though I've got plenty of strength and pickup. Like has been said, nothing crazy, but more than adequate.
I know it doesn't get all that cold down there, but before the snow flies if you're into one of these, also as already said, make sure you have good batteries, a new lift pump, and a block heater. Those three things in good shape I start mine below -25C without too much trouble (manual glow plugs sometimes a must...).