Hi – I will be on a road bike this year, but I have ridden a few prior RAGBRAIs on a recumbent due to a physical condition that I have since gotten taken care of. Here is a very useful thread from about a year ago with some great tips.
https://ragbrai.com/forums/topic/recumbent-riders-2/

As to your other questions:
1) Mornings can be fairly crowded, but I wouldn’t go as far as to call it a bottleneck. You will be fine on the trike regardless of when you start out. The real bottlenecks are heading into pass-through towns, but that’s part of the fun. Trikes are no problem to navigate through tight conditions, you just need to take your time and communicate.
2) You will see pedal-assist bikes of all kinds, including trikes. The big issue with e-bikes on this ride is related to range (most e-bikes don’t have enough range for a 75 mile plus day), and recharging at night. With a trike because you don’t have to worry about balance at slow speeds, even without power you can easily accomplish very steep climbs by making appropriate gearing choices ahead of time.
3) There are more trikes and 2-wheel recumbents than you will ever see in any single event. You will be in good company.

You will see many. You can ride as fast or slow as you want (we all do). You can expect to change lanes a lot since riders are instructed (and most do) to ride right and pass left. Uphill, they stay right and then downhill move left and pass everyone. They then get back over right when neeeded. Mirrors and just looking around a lot is needed. Leaving in the morning can be a bit crowded, but that can happen at any point really all day to some degree. I would not worry about it.

NGN 1
Even without a visual impairment, I found it challenging to keep track of my riding partner. Of course, I was on a recumbent two-wheeler and he was on a diamond frame, so we leapfrogged each other on the hills. You might consider a tandem recumbent. I saw one when I did my first Ragbrai. It looked like two trikes connected by a center pole.

One morning I started about 0630 and had was hemmed in on all sides for the first three miles or so. I usually start at 0530 now so there is only a single file of riders. I assume, though, that you would have to wait until daylight. 0600 should still be relatively few riders on the road.

I don’t ride a trike but I can comment on a couple of things. I echo the notion that there is not typically a huge bottleneck at the start of each day. There can be backups here and there and the crowd is likely to be denser at the start than it is a few miles down the road. I don’t think it would be an issue for most people so probably not for you.

Most pass through towns will have bottlenecks however. People riding two wheelers will have to dismount and walk through town even if they are not stopping. Not as much an issue on a trike, I would assume, but you might have trouble staying in contact with your leader. This is all very low speed so I would guess it is not an issue for you, just mentioning it so that you can consider it and ask more questions if you have concerns.

eBikes of any kind that won’t exceed 20mph in throttle mode (if they have a throttle, many are pedal assist only) and are 750W power rating or less are allowed under Iowa law and RAGBRAI rules. Feel free to bring yours. Others will have to give you pointers on charging them if you don’t have access to a generator. If that generator running in the distance on a hot night is my motorhome you are welcome to plug into the exterior outlet as long as your load doesn’t trip the breaker! If you are bringing your own RV with a generator then you are set. Most teams and charters will have generators that you can use.

You often see trikes travelling in small packs. I can’t tell you if they are doing RAGBRAI together as a team by plan in advance or if they just meet up on the road and in towns. One way or another you should be able to hook up with one.

Come on out in July, you will have a great time!

I borrowed a trike in 2017, due to a broken wrist that happened in May of that year. It was definitely a different experience from an upright bicycle. The hills are where the difference is most notable. You are basically pulling yourself up the hills instead of pushing down on the pedals. As others said here, there really isn’t a bottleneck kind of problem. You will see a ton of other recumbents out there. As you talk to them along the way, many will invite you to meetups and group activities. There were a few hills that I ended up getting off and walking to the top. Keep in mind that my training miles had been deeply restricted due to my injury. One thing I never considered is how much hotter and sweatier I would get because of my closer proximity to the pavement.

I had a great time that year. But it doesn’t take much effort to have a great time every year. Enjoy your ride!
Wendy