The old doors are solid for sure and the old knobs look way cooler than the solid metal stuff available now. The skeleton key mechanism is super easy to remove and replace but needs a bigger slot cut into the wood.

For the crank is depends on what you want. SRAM and Shimano are both top quality and have various model levels. There are power meter crank sets as well but they tend to be way more expensive. I have the power meter crank but my bike came with it, part of why I got it. The Shimano 105 group set is really nice and upgradable.

Our french sliders are wonderful and pretty secure. Not cheap by any stretch but well worth it for the light availability. The newer glass blocks a lot of UV/heat and limits losses better.