Kwb....
I looked at your linked pics & it looks like you once had a Sundowner on your RK.
I'm guessing it somehow didn't cut it since you now have the Mustang installed...?

 

I liked the Sundowner, but it didn't allow the use of a backrest. I tried a one-piece Sundowner with a backrest, but it's a slightly different "fit" than the solo verson, and I like the solo look (I have a large Mustang pillion for touring and a smaller one for tooling round). I really like the Mustang, it's a little lower and wider than the Sundowner and the padding is a little more firm.

 

The lift is a Harbor Freight, one of the less-expensive options on the market. It has one set of fixed wheels and one set of swivels. I have only moved it 10-12" while loaded, but I don't think there would be anything to stop you from doing it. I'd want an extra pair of hands and some tie-downs though! Here it is with my Heritage Springer on it.



During the transformation from a stock ride...

 

Okay, its not a road king but it does have a solo. Mustang Daytripper solo seat is very firm, not squishy. There is no backrest available for this seat.

 

 

Here's my 09 with a C&C solo.

 

the one i prefer. Th best looking for me!!

 

When using a Mustang Vintage solo & Mustang 13.5" passenger pillion on a RKC, can you still use the HD sissybar/backrest & luggage rack (assuming you have the 4 point docking)?
Thanks

 

Picked up plastic plugs at Loewes to fill bolt holes after removing passenger footboards. After that it was posted HD # 90493-83 for footboard plugs.