If I'm reading your original post correctly, I don't think you're exceeding anything. If the weight on the MH tires doesn't exceed 20,500# and the weight of everything going down the road doesn't exceed 26,000#, you have not exceeded your weight ratings. I don't understand what the "tow rating" is that you refer to - I have no such rating on my vehicle. If you're referring to the receiver rating, then yes, you would have to upgrade that item. But, you said in your original post that the receiver would be a 6k or 8k rated unit and the 8k tow bar would also be more than adequate. I don't see where you're exceeding anything. The one previous comment about the ability of the chassis extension to support a stronger receiver is about the only question mark and a call to your MH manufacturer should clarify that.
'04 Journey 36G - Cat C7
'04 Honda CR-V