Hello, Dan.
Not clear what is desired configuration for this second link and do you need any Internet access failover between interfaces, but:
- you could create additional context on ASA and configure it for second link;
- in this case you will loose dinamic routing (not compatible with contexts);
- you won't be able to run one context in routing mode and another in transparent (if you thought about it);
- PBR should be done before traffic reaches ASA (on switch/router).
Do you have any diagram describing current configuration (almost clear) and configuration for second link (including IP-addresses, NAT and routing if present).