Two cents here...for the first time ever, we trailered to Sturgis this year (actually, first time trailering, ever). With the heat being an issue for me as I'm aging (and recent but fixed health issues) and all the COVID BS, it only made sense to trailer if we wanted to go.
I love the Aluma two bike trailers. Light weight but sturdy buggers...however, they are not enclosed. The Aluma enclosed trailers are just out of our price range.
Enclosed really was the only answer. Mainly because of the reasons mentioned previously about keeping the bikes clean and having a garage space at our destination. I searched for about 3 months before finding a real bargain at a place in Bowling Green, KY (Trailer World...ask for Steve). We ended up with a larger trailer than we wanted but it was used, had about 100 miles total on it and was a 2019 model. 7X16, fully finished inside (aluminum walls/ceiling, rubber floor and on ramp, e-trac down the center). This thing set us back $6,000 out the door. If you don't get in a hurry and purchase smartly, you can find a bargain. This thing new, priced with the options was around $8,500.
Iron Horse is just down the road from us in TN. Those things are VERY nice but VERY pricey, resale value or not. While you can use them for hauling more than just a bike, that's what they are set up for.
We have a trailer now that can work for all kinds of things and didn't cost us a fortune. With my Chieftain, I can't use the B&W biker bar (dang it) but second choice was the Wheel Dock Chock...best chock bar none. Easy to load and, following their instructions, much better to tie down without compressing the front forks. We used the bar mount like mentioned above so when we have other things in the trailer, the chocks are easy to remove. We got two, one for my Chieftain and the second for Rick's Skunk. We got model 4's and they worked like a charm, no spacers needed.
With this first experience of trailering and after 3,200 miles, these are the choices I'd make if we had to do it again, too.