I would give yourself 30+ minutes to go from your DL flight at T5/T6 to T2. There is no train, there is a inter-terminal bus that connects the terminals. However, you should just walk straight out and through the parking lots as it is much quicker than taking the bus that has to loop all the way around.

Note that the 30 minutes does not include check-in and security times once you get to T2. Also, make sure Delta interlines any checked baggage to Air Canada so you dont have to pick up your bags and recheck at LAX.

http://www.lawa.org/welcome_lax.aspx?id=256