Once you arrive, do you want/need to leave the area for other sightseeing, groceries, restaurants, etc? If so, the Super C with a trailer would restrict you from doing that unless you are using the Super C for your other running around or you are getting one of those massive trailers that have a lift inside so you can also tow a street legal vehicle with your ATV.
5W Toy hauler would allow you to take the pickup for other excursions.
Some other thoughts:
Stops during travel will allow you to stay "inside" the Super C and you'll have to go "outside" for the 5W. Important if there is inclement weather. Not sure how far your trips will be...may not be a factor. The best solution for one person may not be the best for another.
My perception is there would be more room in the Super C -Trailer combo for working on your ATV.
Many, many other things to consider that I think would be personal preference. Surely some folks who actually have one of these setups can offer better insight.
Do you currently or have you in the past had an RV of any kind?