It looks like I never posted a followup.
I converted a Bike Friday cargo trailer to a cat trailer.
It has been a while since I took Latte in the trailer, and she has grown a lot, but last fall she tolerated it quite well, better than riding in a carrier in the pickup.
Since then I've started carrying Latte loose in the pickup, with a few rules of where she can and can't go, and she seems to be much happier driving. She'll still complain some, but not non-stop.
Like @
Miele Man, Latte's comfy spot is tucked inside of an old leather coat. I haven't tried that on the bike, but she'll go almost anywhere with me tucked in the coat. She'll poke her head out when interested, and push her head back when scared or tired. And, sometimes walk around my back... OWWW!!!
I have a plastic vintage medicine box suitcase that works as Latte's travelling litter box. I've taken it on the bike last fall, but she is less inclined to use it when on the road.
She's grown quite a bit over time, but learned to use the suitcase when she was still quite small.
This was at Bike Friday.
Latte's suitcase is visible on top of the carrier. The litter is behind that.