Hi @Todd_Bryant, as John mentioned you can do bulk data pulls with the REST API and XML-RPC for the remaining data that isn’t available via REST. We have also been introducing Rest Hooks so that you can be notified as resources are modified. Here is the current complete list of supported Rest Hooks with more to come soon.
[
"contact.add",
"contact.delete",
"contact.edit",
"contactGroup.add",
"contactGroup.applied",
"contactGroup.delete",
"contactGroup.edit",
"contactGroup.removed",
"invoice.add",
"invoice.delete",
"invoice.edit",
"opportunity.add",
"opportunity.delete",
"opportunity.stage_move",
"order.add",
"order.delete",
"order.edit",
"product.add",
"product.delete",
"product.edit"
]