Check out both Barr Air Patrol and KCSI Aerial Patrol. They fly oil field and pipeline throughout the country in various piston single engine type planes but they hire "observers" which sit right seat (or back seat with kcsi in their Citabrias) and help spot leaks. About 30% or more of the pipeline patrol flying consists of "dead heads" where you are repositioning from one point of the line to another or back to an airport from the end of a line or whatever and this is where the observers are able to log their flight time. Pay starts around $24-27k from what I've seen with these two companies, but relocation would be required. I dont know a lot about Barr but I flew for KCSI for a while and they are a good operation. You can call their Texas base at 432-523-6228 and ask about their observer positions. Turnover is very high due to people getting their hours and moving on so they are always on the lookout for observers.

I would also do everything in your power to NOT give away your talents at no charge! I hate hearing about new commercial pilots flying with no pay just to build time. There are plenty of dropzones out there that pay, not much, but at least $10 per load in most 182s. Go to dropzone.com and check out their data base of dropzones throughout the country (many in CA). Call them up and then if you can visit the DZs in person that are within driving distance of where you live. With under 500 TT it will be harder but all that means is you have to be more determined and persistent with them. Show them you're a worker and want the job. My first flying job was dropping jumpers out of a 182 at 320 hours TT. The guy I replaced was hired with a fresh comm at 260 something. Just hang around the dz and offer to help out or ask if you can go on a "ride along" just to see what it's like. A lot of pilots see a guy jump out of the airplane next to them with the door wide open at 10k and decide right there dropping jumpers is not for them. Like was already mentioned, banner towing is another great option, but you will need to be tailwheel endorsed for most of them to consider you as the majority of banner towing is in TW aircraft.

And IMO flying into a place in your own plane is a total overkill. Firstly it would be very expensive if you're renting it yourself, and it could kind of give a snobby impression. It shows you're not hungry for work at least that's for sure. Who looking for their first flying job has money to rent a Mooney!? Spend that spare $200 on a perm and zoot suite for the interview.