Hope you found a solution.  This is what I was looking at, but never got around to attaching a trailer.  Looks like it might work...

https://robertaxleproject.com/product/trailer-hitch-adapter-for-rad-power-bikes/

Is it possible to replace the brake pads on radcity 5 plus without taking the wheel off and without taking the caliper off?  It looks like if I remove the cotter pin, I can justt pull them out from the top.  I am wondering if the removal of the wheel and caliper is necessary to put new ones back in. 

Thanks in advance!

Don't need to rewire it. Just cut off the zip ties, moved them out of the way and reorganize them so that they will be out of the way and retie them.  I looked at how they are connected and there is absolutely NO benefit to rewiring the cable.  Radcity confirmed no need to rewire the cable.  Just make sure you can turn the wheels freely without snagging any cables.

I voted as "sure bet" but I guess I can only speak to my own experience.  Received the bike in late April this year. Has ~200 miles.  No problems so far. Worked right out of the box.  I personally think that the rear fender is installed the wrong way from the factory, but that was no big deal.  I didn't even bother fixing it.

I am 5' 6" with 27 inseam. I have radcity 5 plus high step. While riding the bike I am fine. I don't need to set the seat to lowest.

BUT, when I come to a complete stop, I have to get off the seat in order for my feet to touch the ground.  Not a problem for me, as I used to the same with my old bike (short legs, what can you do). I love the high step as it feels more stable and I have easier time locking the frame to bike racks....  I specifically chose high step as opposed to step through, and have no regrets.

I bought a torque wrench for my RadCity 5.  I've had a mountain bike for over 20 years for which I never used a torque wrench, but then again that thing was built like a tank.  I think Rad's instructional videos and guides are HIGHLY "liability" sensitive.  I think it is perfectly possible to assemble the bike (which comes mostly assembled anyway) without a torque wrench and be perfectly safe.  But I don't know this bike and this manufacturer. 

For one, their quality control appears to be a bit lacking.  When I received the bike, I found that one of the fender mount brackets (which need two drilled holes on each) had only one hole drilled on it rather than two!  The other one was just fine. How does THAT happen???  Fortunately, I live in Seattle, and I could just hop on over to the Seattle store and they got me a non-defective one, and helped me to take out a couple of hex bolts (on the head tube for the front rack) that I foolishly stripped. They were perfectly nice.  But I suspect that the manufacturing and shipping part of their company lacks adequate quality control, given the fact that the back fender comes mounted on the wrong (upper as opposed to the lower) holes on the fender as it is supposed to be, and this is a systemic problem, not just mine...  I want to be on the safe side and follow their instructions to the letter in case something goes sideways. 

And also, the ebike's target consumers appear to be older folks some of whom had little experience riding or maintaining a regular bike.  Rad probably wants to make sure that they provide as accurate and safe instructions to them as possible in case something goes wrong so that they can say, "hey, we did everything we could to provide a safe instruction." 

Even though I feel fairly comfortable maintaining a regular bike, I felt that this whole ebike thing is a qualitatively different experience, and I wanted to do it right.  And torque wrenches are a pretty cool thing to own.   

Aluminum, according to the website...

https://radpowerbikes.pxf.io/Mm9442