Does any GPS allow custom routing options??

The current software revision allows you to select miles to the next waypoint or destination. Same choice for remaining enroute time, arrival time, etc.

 

At times....absolutely.

If your Garmin is like mine; when you type in your destination (with default set to "shortest route"), before you click "go", there is a 'thought bubble'. In that thought bubble is a link, click that link, and it will show you miles, time, etc...
If you choose a different route as you go, the GPS will continue to recalibrate the "shortest route"---remember the original numbers before you started your trip...and add a couple hours, since you veered off the original calibrated route, it is no longer the shortest from the starting point.

 

Try the Truckers Tablet. Has alternate routing and you can keep testing alternate routes at a touch with instantaneous routing calculations. At only $279 runs circles around any other trucking GPS and is a pretty good android tablet as well.

 

This is why I have been running Microsoft Streets and Trip on my net book since 2007. It allows you to choose your route by clicking and dragging pretty much the way google maps does. When I purchased, it was the only one worth owning.

But now, I see that S&T has been discontinued (just went to the MS website) so I am looking for a replacement. This really sucks because I have 7 yrs worth of PU and DEL points saved in that software.

I think someone told me Co-Pilot allows you to click and drag to customize your route. I don't know why a truck driver would want it any other way. Good luck to the OP.