A couple other brands to look at which are similar to the Sundowner are InTech, Feather Lite and Millennium. Consider getting a slide in the living quarters to open it up more.
Truck campers can be dropped at a site for use or left at home when you want to just use the truck. Except for the cheapest units, they have four power jacks and quick release turnbuckles allowing most people to unload in about 10 minutes and load in about twice that time if they are new to the process.
In my case, I had a bumper pull toy hauler that had an open garage/living space allowing for 15' of toys, yet was only a 22' model. This was accomplished by having a front bath and the bed in a powered loft or on a jack knife sofa that fit into slide out. With motorcycles, we could still use the loft but slept on the slide out couch when we had the dune buggy loaded. As the number and size of my toys increased, it became increasingly harder to travel somewhere and sleep enrout to the destination with the toys in the way if you did not unload. I really needed 18' or more of garage rather than stacking toys on internal ramps, which also was leading me toward the Sundowner style toy hauler on a gooseneck. This was resulting in 34-38' unit which would have limited us access to more scenic parks.
My second research went into motorhomes towing an enclosed trailer - What I found was many smaller ones are limited to 5000-7500 lbs towing capacity and I knew I would be loaded at 7000+ lbs with toys and enclosed trailer which was too close to limits for my comfort.
My deciding research went toward truck campers. Depending on your truck, these new campers may have no slide up to three and water capacities of 20-65 gallons. We chose a single slide model with on board generator as our first truck camper based on the capacity of my existing truck. It served us well, but we had been spoiled with more space and capacity in our toy hauler and upgraded three years later to a bigger truck and two years later to a bigger camper fitting of that truck. We are happy with our decision and not looking at making change other than possibly a larger enclosed trailer later and I am leaning toward a stacker so I do not add to my length. Currently, I have 20' enclosed trailer with a 10k lb rating on torsion axles. I actually chose a lower riding model so I could carry cars as well as toys, so break over angles were important on the ramp transitions.