It's a bummer that public transport is so damn difficult to use. I can't drive anyway, so most of my travel is done via public transport (although my DF does have a car these days). It's so very expensive and almost always more hassle than driving - no wonder people are reluctant to give up their cars! I imagine it's even harder in America, where petrol is much cheaper - the financial incentives must be even more compelling. So go you for trying, at least! I think if you can cut down on other journeys closer to home (which it sounds like you do anyway) then you can justify the long journeys by car. Another thing you could consider - I don't know if they have this in America, but in the UK there are a few websites which help people meet up to share journeys, so you can save a little money, potentially help someone who doesn't have a car, and reduce the impact on the planet all at once.

I hope you and Doris do get to move in together eventually. My quality of life is so much higher now my DF and I (mostly) live together - it means even when you're busy you get to enjoy their presence, whereas when you're living apart busy times tend to mean fewer visits. It sounds like Doris is slowly coming round to the idea - it's really exciting that she's decided that the rings is something she wants you to share.