API access to get IPs

Have Mesos/ Marathon running on Rancher, and Vamp.io as well. Have Node.js access to Marathon so far (createing Crate.io clusters dynamically). Would like to use Rancher to lookup IP addresses of Vamp LB (master) and Marathon. Have created keys/secrets for the Rancher API. Documentation seems oriented to creating not GETting.

Where is the best tutorial to access Rancher to get access (IPs) of Vamp and Marathon, using Rancher API? so Far have only found NPM rancher-api. Using Node.js/Hapi.js etc. Thanks for the pointers.