I've made the trip you are discussing multiple times since 2018 with various rohloff and belt drive bikes. Never had an issue.
If you are nervous about the belts I'd suggest replacing them before the start of the trip. Or have a friend at home who can next day them to you. So in worst case you hang out in a campground or motel for an extra day. As long as you aren't stuck in Coos Bay or something it wouldn't be a big deal to have an extra day to hang.
Some sections of the 101 have high traffic and poor sight lines. There are also some long shoulderless bridges. On the average there are better shoulders if you drive southbound. You can mitigate a lot of the traffic issues if you ride before mid-May or after mid-September. Lodging is also cheaper in those time windows than during peak summer season.
Generally all state parks have decent hiker/biker camping and easy arrangements for charging an e-bike.
There are usable public transportation options at either end (well, Astoria and Crescent City) to get you back to The World. There is an Enterprise Rent-A-Car in Astoria so you can rent a minivan and haul your stuff there too. There are multiple rental car options at the Crescent City Airport but it will be expensive coming back.
