Hard to say about the transom saver. Depends on your trailer frame, how far up under the boat stern.
For the boat cover: are you looking for just a storage cover, or one that will also work well as a travel cover? You can buy common storage covers from just about any Sportsman's Warehouse, or Cabelas, or West Marine, and many other on-line sources.
If you want a GOOD quality cover that works well for storage and travel, I would recommend getting one custom made for your specific boat.
The ones you can buy that are for boats based generally on length and width, require a lot of paracord lacing and tying.
My current cover was made by Brian's Canvas Products in Freeport Center, Clearfield. It has a "draw" tight cord that pulls tight at the stern, then well spaced reinforced web straps and D rings that I have bungie cords attached to. Then on the inside of the trailer frame I have corresponding eye bolts to hook the other end of bungie cord to.
Custom made covers are more expensive, I know, but my first one lasted 9 years, traveled well, and winter stored outside.
First cover came with boat in 2007, made by Sugar House. This photo taken in my side RV pad in Clinton in Aug 2013.
This photo taken in Sep 2013 with a PVC frame under the cover to help prevent water from puddling.
This photo taken in Dec 2013. Large plastic tarp purchased at Harbor Freight, placed over the canvas cover and laced under the trailer frame. My outdoor boat cocoon.
In 2016, the original cover was beginning to tear at some of the sewn seems. So I got a new one made at Brian's Canvas products in Clearfield. They did an awesome job and put on some additional webbing I requested.
New cover from bow June 2016
New cover from stern
New cover June 2016 left side stern
New cover right side stern
Bungie cords securing cover
Brian's gave me the piece of material (same as cover) that I took to a embroidery shop for the "Tin-Can", then Brian's sewed it to the new cover.
In 2016 I sold my house in Clinton, got an apartment and a storage unit for the boat. So now I don't need to cover the boat when I'm not using it , but I do put the cover on when I take any fishing trips away from my local area. It travels great, and when I park overnight at a hotel somewhere, the cover stays on. It won't stop someone from cutting thru it, but so far, out of sight, out of mind. And it stays dry.