gps recommendations?

[David Rysdam]

My GPS is dying. I'm looking for a replacement, but I want a
particular..."mindset" is probably a better word than "feature".

On a recent long-distance car trip, I found the GPS making opaque
decisions. For instance, it has a route. I take an unplanned exit for
gas and when I get back on, and the GPS has "recalculating"'d several
times, the route is different. Why? I'm exactly where I was before and
the destination is the same. No clue and no way to find out. 

Similarly, I often find that "fastest" and "shortest" are not the only
optimization strategies I could wish for. How about "any route using/not
using road X" or "no tolls, except for this one because it saves 4
hours"? Or "no 'highways' but also don't take me down all these back
country, one-lane roads".

Basically, I find that when I use the GPS, it's the brains and I'm just
the car operator. I want to be the brains and the operator and have the
GPS be navigator. I decide a route (or the backbone of one) and it keeps
me on it.

Does this exist? I know "waypoints" is a thing, but I'm not talking
about visiting landmarks. I'm talking about entering in (most of) my
route and having the GPS handle the details.