Hey @RyanG,
You are correct, for most situations, you will want to have a router between your Modem and Meraki Go Access Point.
While Meraki Go does not recommend using a Meraki Go Access Point as a network router, you can leverage something called Auto NAT, which will give you NAT functionality, as well as the ability to configure Client Isolation on or off. More information about that can be found here. As mentioned, this is not the recommended deployment, and instead, a dedicated router should be placed between your modem and access point.