Logging Intrastate to Interstate

I have to do a load that I will PU from another driver, make one additional stop and then proceed out of state. Pickup in that state and return. I don't remember where you stop using intrastate rules than go to interstate rules, Can anyone explain when I have to change? If I can't figure it out I will just have to use interstate rules through the whole trip. I usually only run intrastate, but the other driver is out of hours...

 

If you only drive intrastate you can drive for 12 hours work total of 16 hours interstate driving is 10 hours driving and a total of 14 hours. There is a a clause in the DOT that does not require logging if you operate 100 mile air radius. But there is a manner to go from intrastate to interstate and back I just don't remember and with the new rules I don't want to drive for 12 hours when I should be driving for 10. This is only going to happen for one day. Thanks for the reply though...