*UPDATE*: Weeks after shooting this, both rear bearing seals began to leak and spatter grease on the back of the wheels despite being removed completely intact. If you're doing this job, just plan on replacing them while you're in there because the seals it comes with just aren't any good.
A whole kit with not only the seals but spare bearings, races, cotter pins and dust covers can be found here: amzn.to/3fLzbv0
Harbor Freight makes a good little trailer, but you may have heard that you need to repack the bearings. This video shows what that process looks like.