I am about to purchase a new router. I want to use my current rt-n66u as an access point. Will all my current wireless items (TV, amazon echo, phillips Hue etc.) automatically connect to the rt-n66u without having to set everything up form scratch?
Yes, i have done the same with mine. I set the new router up with the same details, SSID etc. and everything connects seamlessly to the nearest/strongest wireless AP.
I am about to purchase a new router. I want to use my current rt-n66u as an access point. Will all my current wireless items (TV, amazon echo, phillips Hue etc.) automatically connect to the rt-n66u without having to set everything up form scratch?
Yes they will connect to the WiFi radios on the AP with no problem.
Remember though that your N66 is in the AP mode all router related functions are disabled and now handled by your new router. Any things such as static IPs, port forwarding, parental control, etc. will be handled by the new router.