Amflight Jumpseating
Ameriflight currently has a reciprocal agreement with Southwest, and SWA flightcrew are allowed to jumpseat, although it is by no means as pleasant as walking up a jetway- the SWA flightcremember would have to prearrange the ride, and the AMF captain has to make like the TSA and do a patdown/baggage inspection. I have heard of some SWA crew have taken advantage of the empty seat on most AMF for semi-regular rides, though it's a small number.
Aside from SWA, it is possible for AMF CPs to ride on other carriers, IF the gate agent and Captain of the flight decide to allow it. Out of BUR, it's not hard, but it may change the farther away from BUR you get. Horizon seems to be fairly routine out of PDX, though smaller communities that don't see jumpseaters often can get prickly. Being in CASS helps, but I'm not sure if other carriers allow AMF CPs to ride in the jumpseat since there's no recip agreement.
Also, don't count on getting in the cockpit- the jumpseat is usually reserved for when there is no other option, and it's still the Captain's call. Remember, the only people the Captain is obligated to allow up there is the FAA- on an SWA flight, I've sat next to SWA pilots jumpseating in the main cabin (and had great conversations that way!) I've also heard of at least one jumpseater who nearly killed his airline's rep by sticking his head in the flight deck and saying "Hey, I'm riding with you guys today!" Not smart. Any free seat is a free seat- treat it like gold.