I personally have never fished the salt river. The boat ramp is located at right off Dixie highway where it passes over the salt river. Be advised though, the river flows through the Ft. Know military reservation, and a good portion of it is off limits. The only area of the salt open to the public from that ramp is just east of the ramp to where it flows into the Ohio, or approximately 1/16 mile.
Hope this helps.
Keep on chuckin'