I have a long story on how I outfitted my Prius but here is the Reader's Digest version. I got my hitch from
http://www.coastaletech.com/. No special drilling. Easy to install. I got the 2" receiver but I could have used the smaller one. They are both Class 1. It did not come with chain loops so I had them welded on by a shop in Richmond. Just pulled up and asked them to do it. They took some muffler U-bolts and welded them on. They work fine.
I got the 4x8 chassis from Harborfreight and built it with some minor mods (painted black, cut off stands, locked down folding hinge, moved the wheels back, replaced the square fenders with round, etc.) Jamie Miller at Happitrails.com built me the cab and shipped it. I replaced the leaf spring axle with a 48" torsion axle from etrailer.com. Much smoother ride than the leaf springs. Total outfitted weight is 650# Use a 2.5 inch drop hitch and mount it upside down to get the trailer to track level.
Pulling it by myself with minimal stowage is fine. With 3 other adults and their junk, the ride suffers. I can still cruise but uphills are a struggle. Gas mileage with all the extra weight really suffers. only get around 25 mpg, especially trying to cruise at 70 mph or more.
I hope that helps. Jump in. The water is fine.