Re: integrate to a different WordPress
What I would try is getting bbpress site 2 using the WP 1 users directly. Try using the cookie information from the docs:
If bbPress is not installed in a subdirectory of your WordPress install, you’ll probably need to adjust both bbPress’ and WordPress’ cookies to meet your specific requirements. Below is a brief outline of the variables and constants that control the cookie behavior in the two programs.
PHP bbPress WordPress
name $bb->usercookie USER_COOKIE
name $bb->passcookie PASS_COOKIE
path $bb->cookiepath COOKIEPATH
path $bb->sitecookiepath SITECOOKIEPATH
domain $bb->cookiedomain COOKIE_DOMAIN
Trent