Hi purplesmoke. I'm a Caltech undergrad in EE (rising senior). 3.65 is (as far as I know) a relatively reasonably GPA (meaning it's a possibility, but it's definitely not going to be stand-out). Also, how your GPA is considered does depend somewhat on where you went for undergrad--a 3.65 at MIT is more impressive than a 3.65 at Florida State.
Who are you working with for your SURF? I would try as hard as possible to connect with your professor--Caltech is small enough that if you develop a good rapport with the prof and he wants you to work with him/her, you'll most likely get in. If you're working at JPL, at the very least meet with profs you're interested in.