I have towed toad with dolly, 4 down, and trailer. All have advantages/disadvantages. Trailer biggest disadvantage to me is when I take mine in for service (about once per year) with not currently having a 4 down option. But that is the biggest inconvenience I have experienced.
As dvmweb pointed out, there are several threads on this so I encourage you to do a search.
I love the trailer, the cleanliness of my vehicle/vehicles, security, lack of damage (road debris etc), flexibility of taking whatever I desire or taking both my Harley and vehicle, extra storage, extra room at events/parks including sleeping area, many advantages.
A little planning campgrounds will not be an issue, storage of the trailer hasn't been an issue for me, usually stayed hooked up but sometime need to unhook and usually get to keep it very close for accessibility and to date I haven't paid anything extra in storage fees while on the road.
Make sure your hitch and coach can handle the weight and the tongue weight, I wouldn't worry too much about length if you are talking about 18-20' trailer even if you have a 45' Dutch Star, but I would not get too short of a trailer. I would also pay attention to the height of the door opening in case you decide to take a taller vehicle.
Some other points to consider on the trailer, plenty of axle capacity, good brakes, lights, dove tail, reinforced ramp door and floor to handle the weight, 'e' track in the floor for various securing points and 'd' rings. I have found with the flexibility that I also need to load differently for tongue weight, for instance I back my Escalade ESV in which allows less tongue weight and more room up front for storage.
As stated, lots of good information and if you get serious about the trailer, feel free to PM me after you do some research on here because there is a lot of great information. Good luck!
2009 American Eagle 42'
Trailering HD Road Glide and Saab 9.3 or Cadillac Escalade ESV