Yeah bolts in particular are terribly rust-prone. Paint them with boiled linseed oil. Very effective and it holds up good. Before and after:
averaging 50 MPG here according to the Fuelly app, 4100 miles in to owning it. I think if I lived in a more congested area I'd get better MPG, but the open highways, and expected speeds on the open highways, reduces the MPG.
The only issue ive had in 83K miles is the rear passenger door lock actuator worked randomly like yours. I picked up a used from on eBay from a totaled prius for 99 bucks and its been working fine for about 20K miles