Hi Taylor,
I can confrm that the two ports on the R720 are bridged (in hardware) so it is possible to daisy-chain devices using the R720 to connect on both ports.
Please note that only the 2.5Gbps port can be used for PoE power to the unit, so this may scupper your plans for uninterrupted service unless you plan to power the AP using DC power.
Please note the R720 is PoE power hungry and in order to enable the 2nd Ethernet port, the AP requires at least 33.5W PoE power (802.3bt PoH).
I hope that helps,
Darrel.