I've doing a fly-in trip with 7-9 people for the past few years and here's what I've found:
It works well to have a "cargo" carrier and passenger vehicles. Easier for packing, more comfortable and generally cheaper.
We used to rent a cargo van as the cargo carrier, but a lot of the new mini-vans now have fold flat seats for the entire rear area, not just the rear row. This now allows minivans to function as cargo carriers. 7-8 suitcases and 7-8 board bags take up a huge amount of room. You don't want to use the "ski" racks that rental car companies might equip their vehicles with. They usually are the cheapest things, only hold skis and you have to take the skis out of their bags to fit. Be careful with renting true cargo vans, however, as most credit card insurance plans expressly state that they don't cover cargo vans or pickup trucks.
2 mid-size cars are often cheaper than one mini-van. So if we're 8 people, then 2 go in the cargo carrier and the other 6 go in 2 cars with just their carry-on luggage. And if there's no luggage, then mid-size cars work just fine.
Bear in mind that we're often looking at a 3-4 drive from the airport to where we're going so comfort is part of our calculations.
Checkout the price of a weekly rental. You can always take it back early and be charged for the full week, but a full week is usually cheaper than 4 days and you tend to get unlimited mileage. I've got a minivan booked already for $300/week and the daily rate is $70.
Last edited by Bones; 11-06-2012 at 10:37 PM.