I agree with Caleb on the 33’s and a locker being a good choice. My son took is Tacoma with a 3” lift with 33’s on the trail and I only needed to strap him once, across the obstacle below on the way out. He did however add a few new scratches on the front and rear bumpers.
I would say the flash flood risk is very low. Most of the trail (98% ?) is open country, there are just a couple of canyon areas and I don't think they would have much drainage from higher ground.
Steve, I have done Hole in the Rock in the spring (May) and in the fall (Oct). The spring trip was very windy but the fall trip was beautiful. This is my 2-cents worth, others may have their opinions.
Also the light scatter is a big problem in a snow storm, the reflection coming back at you will almost blind you. DO NOT put HID's in a housing that is not designed for them, they only cause problems for yourself and the other drivers.
I have had my Expedition One for over a year and it is great. The fit and finish is fantastic, the gaps are small and lines fit the JK perfect. In my opinion there are none better.
If you want a 700R4 built I know a guy that builds 100's of them a year. Nearly every Hot Rod in the valley has one of his transmissions in them. I have one of his 700R4's in a ElCamino behind a 496 that runs in the 11's with slicks at RMR, no problems. PM me for his number.
The last time that I was in the swell was over 25 years ago. We would go in through Oil Well Flats, down Fix-it-pass (at that time we called it pucker pass) and out the racetrack. Most of the trail was difficult to find so we spent a lot of time looking for the trail.