That's the right place to start, but be aware that the van cutaway chassis used for RVs will have a somewhat different configuration than a standard passenger or utility can. If there book shows an "ambulance" configuration, that may be closer.
Typically the van cutaway version has the largest available radiator and alternator and that results in different belts and hoses. It will also have whatever heavy duty suspension option was available, and those options don't always show in the part store book or computer. It's not unusual for the wheels and brakes to be larger than standard as well. Often the parts manufacturer or distributor has additional information, so ask the store clerk to contact their suppliers for help. NAPA and Carquest stores are more likely to be able to find the right stuff than consumer stores like Advance or Autozone, but check all the stores near you to see who is best for your needs.
