I had envisioned a van-based system for the last-mile rail problem. It's a more comfortable ride than a bus, and since you're focusing on short routes you should have pretty low latency with the vans, which fixes the "transfer issue" where transferring between two transit lines can add 15+ minutes to your commute. Van drivers are significantly cheaper than bus drivers, since a normal drivers' license can be used for up to 15 passengers in most states (you probably still want to vet them).

I've been semi-expecting to see UberVAN pop up actually. It doesn't seem like the kind of idea strange enough that nobody else would think of it.