The 76csx is the same hardware as the 60csx, which is one of Garmin's most popular models ever. The only difference is that the 76 floats and the antenna is located inside the case. I still have my 60csx, but don't use it anymore. I think the screen resolution is too low and processor too slow for a modern device, but others still seem to be happy with it.
Why do you think that Garmin doesn't make maps for it anymore? AFAIK, it will work with any of Garmin's maps as long as you have the newest firmware installed on it. Just about any of the maps on this site should also work on it - give it a try. It is not compatible with raster imagery however - such as Birdseye or "Custom Maps" (.kmz files).
So, I think it's really up to you as to whether ~20 year old technology is acceptable. Try loading some maps on it and using it before your trip.