We foolishly got rid of our bike trailer when our oldest 2 were biking solo & now are wanting to get a new one.
Only needs to be able to carry 1 kid (currently 2 years old)

Looks like Burley doesn't make the Solo anymore.

Any brand suggestions to look into, will be towed behind a Marin bicycle, don't need any stroller conversion or anything like that, just a kid carrier trailer.

Burley and Thule (pronounced too-lee - started in Sweden) seem to be the two big brands.

I have a Burley here and a Thule at a vacation place and there isn't much difference between them. Construction and function pretty much the same, just minor differences in how the pieces connect to each other.

Within each brand there are more and less expensive versions with more or fewer features like suspension and ventilation panels, etc.

We have had a Burley Bee for 6 years and still love it. My kid is 7 but is a small child so it still works well for us.

Not quite what you're looking for, but we had one of these when our kiddo was little. It was a lot of fun.



https://rideweehoo.com/

^ Their Blast model (non-pedal) might fit the bill, but sold out currently.
Didn't think about this style & hadn't seen one with a harness before.