Thanks for all of your help w32pamela. Your solution didn’t exactly fit my needs but it definitely put me 80% there. For others in a similar boat, or rv, here’s what I did.
I started from booting the hAP in a Dual Home AP (check the quick sets), keeping the the Internet Acquisition to Automatic. From there I went into Interfaces >> Interface and set Ether5 master-port to “none”. Then I went to Interfaces >> Interface List and changed the WAN from Ether1 to Ether5. Next IP >> DHCP Client and change the interface from Ether1 to Ether5. Next IP >> DNS and set that to some local DNS. I used 8.8.8.8 and secondary 8.8.4.4. It looks like the NAT settings are fine with the defaults but I’m also not super familiar with them so I’ll keep looking into that. I left Ether1 open for a hardline for now, but I may try to change that in the future.
Thank you again, w32pamela! Hopefully this helps someone along the way.