going to be taking my first bike tour down the coast of California with my 65 lb dog. Any tip and advice on what type of bike i should use as well as some sort of trailer for my dog? Budget for the bike is sadly around 800

I have a Walmart schwinn trailer that I really like...it was something like $150. It is reasonably light (aluminum frame) and has 20" wheels. It has a "trunk" area where you could store some of your stuff and there's plenty of room for a dog inside. You might want to make sure the floor is comfortable for the dog to lay across - on top of your sleeping bag and pillow maybe?

If I was dragging a 65 lb dog up a hill, I would look for looooow gearing - like 22 or 24 small ring on a triple and 30+ tooth big cog in the back. Any bike that can hold a couple of racks, fits you and is comfortable will work. It doesn't have to be expensive - just comfortable and properly prepped. Make sure the hubs and crank are adequately greased. I would look for a 90's mountain bike and put slick tires on it...and maybe some bar ends to give yourself a couple different hand positions.

+1 to 90's mountain bike. The steel ones are built tough, almost all have rack mounts, and good components can be had for cheap. My girlfriend's early 90's Kona Cinder Cone was $200 for Shimano XT everything.

My vote goes to a solid 90s steel MTB off craigslist.

My commuter price tag:
Bike 60$
Tire 40$
Rack 20$
Lights 20$
Plastic lining 10$
Tubes 10$

160$ For a reliable Chromoly lugged steel beauty.

As above, I can't see paying more than $200 for an 80s or 90s steel frame bike on the local used market (depends on where you live, probably), then another $200 max to repair and upgrade it to my tastes and needs, including excellent new tires for a tour. Can't help with the trailer, but best of luck touring with your dog--some friends do that on their tandem and they all love it, including the dog.

Agree a mountain bike with a very low range for the extra weight.

I'd suggest that with whatever trailer you buy, add a solid floor. Maybe a thin piece of plywood or something. There's a good chance the nylon stretched across the bottom of the trailer will tear and/or wear if you don't.

If going with a vintage mtb for touring, I'd swap out the existing bars for trekking bars. It's an inexpensive conversion since the shifters and brake levers will work on a trekking bar. The trekking bar gives you the advantage of multiple hand positions in, IMHO, works better than bar ends and the like.