Actually I think Tommy's suggestion is pretty valid. A sidecar would be a reasonable consideration when it comes to the choice of how to get to three wheels, in that neither a sidecar rig nor a trike kit are going to fall over, but the sidecar does have utility that a trike doesn't. I think Tommy C was right on target.
But - if you're instead only considering three-wheel trikes, I'd take a decent look at this one. It's different, and it looks like it retains the fun of leaning:
Actually I think Tommy's suggestion is pretty valid. A sidecar would be a reasonable consideration when it comes to the choice of how to get to three wheels, in that neither a sidecar rig nor a trike kit are going to fall over, but the sidecar does have utility that a trike doesn't. I think Tommy C was right on target.
But - if you're instead only considering three-wheel trikes, I'd take a decent look at this one. It's different, and it looks like it retains the fun of leaning: https://www.youtube.com/watch?v=t30NU_v5YcM
Another option is to just trade in the current bike on an existing Harley trike. Certainly much less hassle, and may also be more cost-effective.
As for conventional trike conversion kits, I'm sure someone else will be along to discuss their experience with those.
I would recommend first selling your RK and then buying a new "end of model" three wheeler of your choice.
I was in this situation several years ago with my '13 CVO but I couldn't see spending that much money for a conversion that would add little value to the bike (if I wanted to sell it).
Conversions can vary greatly in cost, depending on what you're wanting.
A body/trunk/tour pack conversion can be very pricey and you would then have a 16 year old trike
A simple conversion (no body/trunk) would be the least expensive unless you want to go with a Voyager unit that can be quickly be added/removed from your bike.
All of this should be considered, as well as the type of riding that you will be doing and for touring you want a later model touring style trike.
The other issue with any older motorcycle/trike (especially modified) is finding service as some dealers will not do work on a machine that's past 10 years old.
My wife has ridden a trike for over 15 years now. We have owned conversions & HD factory trikes. The advantage of a factory trike is if you travel most any HD dealer will work on them if you have troubles while on the road. Not the case with conversions, some dealers are reluctant to work on them. If you are thinking conversion, in my opinion Fat Baggers Inc (FBI) has the best handling one. Have owned Champion & California Side Car trike conversions also.
I bought a Frankenstein trike kit for my wife's Sportster. The quality is excelelnt and the install was easy. I recommend that you also buy the triple trees to correct the geometry.
Two plus years ago we converted our 2018 CVO limited into a trike with a Roadsmith conversion and have been very pleased since. In my opinion the two best conversions to consider arer Roadsmith and CSC. CSC has the sexier (and wider body) with a huge trunk (nearly car sized). The Roadsmith has the option of an aux fuel tank witch allows me to travel farther between fill ups than my friends still riding 2 wheels.
You will never get your money back out of a conversion, but the ride of a good conversion with Independent Rear Suspension is head and shoulders above that of a TriGlide with a solid truck axle.