Before committing to a bumper carrier of some sort take a long hard look at the multitude of choices in small motorcycle trailers. I am currently on my third and hopefully last trailer. Recently sold my Kendon folding trailer replacing it with a 6 X 10 {14' overall} cargo trailer. The Kendon worked very well and had the added advantage of standing vertically against the wall in the garage with a very small footprint. If storage is an issue check out the Kendon line.
I like the added protection/security of my new cargo trailer but you have to store it somewhere {mine cost me an additional $15 a month as it just lives behind my Clss C in a slightly longer slot at the storage yard}.
Adding the weight of an MC to the rear of a Class C is tricky. You will at the very least need to add air bags - I just did to deal with the extra hitch weight of the single axle Cargo trailer... and they help a lot. You will need to end up when all is said and done with 33 per cent of your coach weight on the front axle and be careful not to overload the rear axle.
Several trips to the CAT Scale were necessary for me to get things right. If you would like any pics of the various set ups I used just send me a PM as I no longer have the ability to post photos here.
:C