[crazyblazer87]

So for the key, that ignition switch is known as the WIN module. Caravans used to always do what your problem is. I always had to change the module. You will need to get a scan tool so to get through the key security with also getting the security code from the dealership so to get the module programmed. Dealership can give it to you if you bring proof of ownership with you to the parts department.
Second, depends on what the code is for the emissions. The dash stating tighten gas cap is a dummy light pretty much. The car has detected a leak/ problem with the fuel vapor containment system. That could be a number of things. The leak detection pump (E.S.I.M) common failure, purge solenoid, any vapor line cracked, fuel tank/pump leak or rusted, charcoal canister to name a few.
The cruise control could be because of the abs problem. I would figure that out first to see if cruise control came back. You need to first find what fault code is present to even know where to start.