If hotel guests knew in advance that the parking lot was somewhere else, and there was a series of shuttles taking them there, and absolutely no one was taking a room unaware they can figure out themselves if they want to stay there or not; I agree the carpark was fairly full last year, but not that full as a big chunk of it was used for the banquet for at least some of the period, I never had an issue getting a park there in the days before the race as I had a parking pass.
Some of the ppl I know staying there didn’t have cars specifically because it’s a s**tshow renting cars in Kona, and one of the benefits of that hotel is that you can get by without one; ramping up more shuttles to the airport, buses etc and it is painful with a walk uphill, but doable with enough shuttles. A deal with all the usual places where people park cars race day now (I think Costco is one, there are a bunch of other strip malls etc nearby) and again, painful but doable; other race locations in the world have to do this sort of stuff too.
Race day you can’t drive in or out anyhow, so that day is a non issue. So it’s extending that to 2 days. The parking lot is big enough to still have some cars in there, just not full. And with a valet system you could jam in 2-3X more cars as we do in Asia double triple parking etc throwing staff at it, again…painful but possible.
The bigger issue is whether the island can handle that number of guests; however a lot of people are there husband and wife where one isn’t able to race currently, so maybe it isn’t a 2X more people issue. Of the locals I spoke to (non representative sample obviously but seems to be the vibe of many posting in this thread) they didn’t mind the event, they were saying pretty much 1 day is ok, 2 days actually is 3 days of disruption…too much.
Regarding crowding on the course, spreading out the waves a bit more and adjusting cut off times (also previously discussed a bit) for all AG other than some physically challenged or 65+ cut off more like Roth 15 hours, make sure the last AGs are more like the 70.3 waves not the absolute oldest ppl, and that still gets everyone off the course by 12am even though some start times later.
It isn’t ideal but trying to push more ppl onto a single course in a single day with the limited size of the pier and the issue of conjestion on the road plus lack of accom seems to be the 3 big constraints. So rather than aiming to double, perhaps having a +1000 additional slots is reasonable and doable rather than trying to magically double it from 2500 to 5000 instead going to around 3500-4000 ish, while maintaining Kona as a prestige hard to attend event, and enables roughly equal participation MF as seems to be an Ironman non negotiable. Getting 1750-2000 women to Kona is already a lot; 2023 was only a bit more than that. 2024 males were 2400 so that drops to 1750-2000, but 2024 had a backlog from the 2 day split Nice anyhow AFAIK so would still be a reasonable challenge to qualify.
At end of day IM will decide all this, just spitballing really how it could be done someway somehow.