I have Openwrt installed inside of proxmox on my hpt730. It is currently behind an old router. The current gateway is 192.168.1.1. Proxmox is set at 192.168.1.216 and Openwrt is set at 192.168.1.235. When I go to make the switch to Openwrt, what network configuration changes do I need to make in Proxmox and openwrt to make sure I get up and running with no problems?
Not a good idea. Remeber that any maintenance/issues on your proxmox will render your internet connection useless.
Having a dedicated device is the recommend setup