Hello Drew,
Evinrude had some really good engines back in the day. Be sure you avoid any Evinrude FITCH engine. Those were rushed into production with a German electronic fuel injection system without engineering other systems to match. there were multiple recalls that were highly dependent upon skilled mechanics. These engine all had cowlings that were labled with the FITCH. That could be removed by now of course. The XP's were good engines but 20 years of use is long run to consider now using on an regular or extended basis. The FITCH production actually put Evinrude out of business to be bought by Bombardier. Other than this series you would likely have what was a good engine but the age would scare me off unless willing to spend significant money on it. Certainly, the older equipment is subject to have issues that you can't eaisly detect that could be costly. If you can move up to 10 years old or less your odds are much better at landing on something that will carry you further. Drew, this is just my observation- I bought numerous used boats over the years, not a single one did I ever test drive first and a couple sight unseen.
I never had a single issue with one of them other than regular maintenance- but I always stayed under 7 years old in my search. There are mostly good used boats out there to pick from- so good luck and be careful..