Do you recommend unhitching the dinghy over Monarch Pass?

If you are marginal on power, it would be a good way to ease the load on the MH.

If you have sufficient power, it won't hurt but less of an issue.

Assuming the CRV driver knows to down shift to keep the speed down instead of using the brakes I would unhook it. West bound from the pass is a long steep downhill where you need to go down slower than you went up.

We did Monarch many times with our formally owned E450 V-10 powered class C towing a Jeep TJ. Supplemental braking on the Jeep, paying attention in keeping RPM up when ascending and using correct transmission gear when descending made the trip possible. We did disconnect once for the trip over and it did make it much easier so, if you have your concerns and have a second driver, unhitch and go for it. Otherwise, if your Class C and towed CRV are up to the task, it is doable and is done by many.

It will definitely be easier on your Class C and not that big of a deal to accomplish. I went over a really steep section going into California on IH8 with a 30' Class A (Chevy 454 engine) pulling a Suzuki Sidekick and really struggled. Sure wished I had thought to separate them and let the wife drive the Sidekick. It was the first time on that route and didn't know what I was facing.

“can be challenging for those not used to mountain driving.”

Reread all the mountain driving tips and meet the challenge!

I thought I would post an update to my question concerning Monarch Pass. We successfully drove it a few days ago--with our toad disconnected. It was slow driving, but we survived! It was definitely worth doing. Thanks for the encouragement and advice.