for the front porch, just a few simple changes: definitely replace the front door like you said.

the rest would be easy: modern house numbers, a few assorted potted plants, updated porch lighting.

you can get sconces like this just about anywhere. I have the round one on my midcentury and think it's super simple and cute.

or you could do something more trendy. google "MCM" porch sconce to get a ton of ideas. make sure it's rated for outdoors though.

one other idea but it would be major: I like the bricks for the walkway, but replacing the porch and the rounded part with wood would look better. I wonder if a concrete porch can be clad in wood (maybe that would cause a water issue) or if all that would need to be demoed first?

also, I like your idea of cedar around the windows, but really, you could probably just get away with painting the white trim a dark color, like in the first photo I posted above. it would especially look good if you redid the porch in wood.