If you have limited storage space - the hitch mount hauler takes up the least amount of room. I have seen them used for 250 pound dirt bikes and they are easy to load......start getting up toward 400 pounds and I think it would be scary to load. When you get the bike up to the height of the hauler the handlebars are going to be up at head level!
An open trailer doesn't have to be horrible on fuel mileage - if you get one that doesn't have the large ramp that raises up like a sail. I had a small open trailer and you really didn't know the trailer was back there.
Little trailers like this are for sale on Craigslist frequently......this one is a bit rusty - but is a good example of what they look like.
https://cincinnati.craigslist.org/mpo/d/sardinia-motorcycle-trailer/719813328...I have a small enclosed trailer that also functions as my room while camping. I like being able to haul a bike and have it secure and dry - it is nice driving through the rain on the way to the mountains with my bike out of the weather. I also like having the bike locked up on those nights when I have to stop at a hotel while on the way somewhere........I use this trailer a lot. I haul it with my little 4 cylinder Pontiac Vibe and I get 32 mpg without the trailer, and it drops to 25mpg when I haul the trailer.....the convenience is well worth the extra cost of fuel. The trailer is 8' long and 4' tall inside, and the rear door opening is 45" tall - most standard motorcycles fit inside and with a Savage you only need to remove the mirrors to let it fit. On the F800BMW I have to remove the windshield......I have bar end mirrors on my Savage Cafe and it fits without removing anything.
I hauled my Savage back from Long Island New York to Kentucky, been to TN/NC/GA countless times. My wife and I have used it for weekend camping trips, I have hauled furniture, lawn mowers, and other stuff in the trailer.......when it won't fit in my car. I bought the trailer used from a fellow who hauled rabbits all over the country in it - he installed the windows to keep the rabbits cool in the summer.