If I were renting I'd be looking at the ski shop rental options where you pick the gear up the night before ski day one and return it after your last ski day.. No way I'd deal with filling out forms and waiting in lines every day twice a day.I posted a thread about Silvercar in Denver which rents Audi Q5s with ski racks. Personally, I think it would be less hassle to bring skis, rent the car with the rack, and not have to deal with rentals on a daily basis. Definitely bring your own boots.
If the kids are little, rent the gear for them. Enough to juggle getting little kids through airport logistics without dealing with their ski gear too.
This is why I always prefer to drive, time permitting. I'd happily give up one full day of skiing to have my own vehicle with all our own gear for the other days.. than fly and rent everything to get one more day on the slopes, maybe even two more days when talking about an entire week plus..