In addition to what's already been mentioned:
I know you said you don't usually check bags, but if you do, you can check up to 2 bags, which can be overweight (each can weigh up to 70 lbs.) with no additional fees for the bags being heavy
If you need to check in at the airport for whatever reason, some airports have a separate line for Sky Priority (although it isn't always shorter!). Silver isn't Sky Priority, but IIRC, the signs usually say, in small letters, "and Silver Medallion."