Although some instruments and electronics may look like museum pieces, there is a real advantage to a single PO and original equipment: you probably don't have the crazy mystery wires that have been run and abandoned for a variety of upgrades or custom electronics that were installed by multiple owners with varying levels of skill or experience. As one skipper noted here, you really don't need a wind instrument to tell you how hard the wind is blowing or where it's coming from. I wouldn't go up the Columbia without a depth sounder, though. The sand bars shift too often. Although time consuming (and not inexpensive), rewiring the DC Panel, removing the infamous trailer plugs, running a new NMEA backbone, and installing new transducers and instruments is one of the more satisfying and, IMHO, one of the easier tasks to do yourself. One joy of boat ownership is that it provides an opportunity to acquire tools, and the tools really do make the tasks possible. Once you have the right tool, and have used it once, you probably want need it again for years, but someone on the dock will. . .
The documentation provided here for projects on our boats is immensely helpful. From electricians and aviators, you will find examples of some electrical work that is pure art. Others of us have built systems that will stand the test of time (another 35 years?!), but we learned some things the hard way, and the end product is anything but elegant. Still, she sails just beautifully.
Tradewinds has always been a fresh water boat, too, and I believe that adds years to many parts of the boat, especially the metals that suffer from the long-term effects of salt and galvanic corrosion.
Looking forward to hearing how the survey goes!