I think I missed what you were driving at. Swampers will be fine, just air them down. I do the Rubicon on "normal" tires. And air down to 15 ish. Swampers if bias ply may need to air down much lower. I would not buy new tires to do Rubicon. It's a great trail but not crazy hard. It's just normal hard. And it's dry(mostly). I've run it on various MTs and ATs and they are fine. But you want good side wall strength. Don't over think it.
I've done HiTR 6 maybe 7 times! Love that trail! I hope to do it again a few more times. It's a fantastic adventure and a personal favorite. I love the scenery, the camping, and the hike at the end. And the historical story.
It's an apples to oranges thing. They are very different experiences. Rubicon is a challenging trail but not impossible. And I'd say Rubicon is harder and different than HiTR overall in spots. You don't have the assurance of great traction like you do on HiTR. And there is great remote hiking at Rubicon too. You can hike up to Rockbound Res, or over the slabs from the springs back to Buck Island. It's all about what you want to do. Many years, I've hiked from Buck back to Loon starting at 6am. It's kind of surreal and awesome. You see the Rubicon from your 2 feet through every obstacle and squeeze. 2 years ago we hiked the old haul road back to Loon at the boat in campgrond, then got lost in the granite, then saw trucks above us and realized we had found the Rubicon trail again. It was like 13 miles lost on the granite but it was pretty fun.
And if this group goes down and does Dusy after Rubicon, you will be well versed in Sierra trails. I'd love to commit to that but just can't. Dusy is my favorite overall trail. But it can hurt you due to the remote nature of it.
I hope you guys do Fordyce. It's definitely harder than Rubicon, but mostly because of that first crossing of Fordyce Creek. After that, it's the usual Sierra Rocks and boulders. I've have the most difficulty on winch hill #4. Most will need to winch, which in my view is OK. Winching prevents damage and problems later.
I'm capping this at the confirmed 11 drivers below. WITH THE EXCEPTION of any participants of our previous trips out West. @TRFCSUX , @Pacer , @SAS , @Jakes40 . I hope I didn't forget anyone.
With between 10-15 trucks committing when it all comes down to it, there will be plenty of passenger seats. However, passengers will be required to stack rocks, pull cable, and earn their seat (bring booze/food).