In GoldWave and other Wave Editors, Select Edit > Compression > Reduce Peaks.
There will likely be some presets which will work for you. Pick the most offending area, and run a quick test of a second or two. If that brings it below 0db, then you are golden. Then apply that preset to section. If you made the least aggressive compression preset which will bring that section below 0db, then it won't affect the rest of the tape, and you won't have to compress the whole show, only that section.
But your eyes will be proof of that. Run the presets on a couple of short sections to see what the result might be.
Unless the section looks like a 2x4, I don't sweat compression too much; most of the time it is just symbals and handclaps which are the offending noises; Indeed I do add a little compression to every tape to reduce the dynamic range, and bring those peaks down a tad below 0db.