I hope only one of those is running the hotspot.
WAN and LAN IP ranges of the E2000 should not conflict. You can set the AC66u to 192.168.20.1 and the E2000 to 192.168.10.1
Hotspot remains on 192.168.182.0 from the Hotspot configuration.
However hotspot throughput would be limited compared to the 200Mbps please note.
E2000 should be run on this firmware: http://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2013/07-24-2013-r22118/broadcom_K3X/dd-wrt.v24-22118_NEWD-2_K3.x_mega-e2000.bin after a proper reset(administration>Factory defaults). saving/Loading the configuration is not recommended and will mess the configuration.
Local DNS setting of 8.8.8.8 is highly recommended on SEtup>Basic setup page as well as disabling DHCP server for the hotspot router. Hotspot itself is assigning addresses. All of these are covered in the DD-WRT guide in more detail.