Static IP for Router set in bridge mode
Solution 1:
You should definitely turn off DHCP on router A as this can complicate things, and you should probably assign a static IP address to "router" b if you are going to be using the web UI of the access point at all, otherwise you will have to check what address it has been assigned every time from the main router. As for the delay, it could be a number of things, you might want to check out the configuration of the access point some more. It could be a slow cable, old firmware, router b is set to older 802.11 -- What happens that you have to reboot router so often? just takes indefinite amount of time to connect wirelessly?