Taking 4 year old in car seat

[focus22]

My husband and I have a wonderful 2005 Rialta HD and would love to take our 4-year old granddaughter camping later this month to get her excited about the joys of camping with us. We know she needs to use her car seat. Has anyone taken young children in their Rialta and if so, could you please tell us how to use the car seat and make it safe for her to travel with us. We don't plan on a long drive this time, but know that doesn't matter. We want her to be safe. In our model we have the rear facing bench seats and the barrel chair, not the two extra seats behind the driver and passenger seats. Thanks in advance!