Is the customer's hosted account management info synced to SFDC?

Yes, if you have the Account Management Pages enabled under Hosted Page Settings, then every account's hosted login info will be synced over to Salesforce.

The login token sent to the Recurly Accounts object under the field "Hosted Login Token". Keep in mind that you will not see the entire account management URL, but rather the unique token for that customer.

For example, you will see a token populated, such as "ABCDEFGH1234567" in that field. You would add that token to the end of your login URL, which is YOURSUBDOMAIN.recurly.com/account/. 

Therefore, the link that the customer would use is YOURSUBDOMAIN.recurly.com/account/ABCDEFGH1234567.