If you check in at T1, and then walk to the far left, past the Elite check-in and Elite security line entrance, there is a separate security line that leads directly to the security-side 'bridge' that links T1 and T2. Note, this security is closed when sometimes, but if you are leaving during 'regular hours', it should be open.

I think that the shuttle runs every 10 minutes between the two terminals. Probably 5 minutes or less for the actual ride.

BillJ