Yes you can delete now But if you were to fill the memory then you would not be able to delete the route.

 

Thank you very much 14CVOUltra for your time and helping me out.

After all the threads I've read and stuff on the boom GPS there sure is a lot of hackish advice out there.

 

The way I understand Select All, if you make a route and use Select All to load it, it will load your GPS setup choices too. So if you have waypoints sending you on an interstate and your GPS setup choices was "avoid highways", it'll try to get you off the interstate whenever it can. It'll change your route to make your setup choices work.
I used to think Select All was the way to go, but was informed on here that it wasn't. I think when I used it, that I was just lucky that my GPS setup choices just happen to agree with my route. Someone with a bigger brain than mine can reply if I'm wrong about this.

 

I'm replying but not on the basis that I think that I have a bigger brain than you. Also, I can't answer your question in respect of what "all" actually does. Everybody here says "don't do it!" but no post ever, which I have read, has actually described why it is a bad idea. I, personally, still think it is not relevant if and when you do the following:
Do not set any avoidances and also set the routing option to "fastest".

Now, obviously, this will potentially screw up your routing - but only if you do not force the routing via waypoints: if you plan a route with e.g. Rideplanner and set waypoints in such a way that the route is displayed/routed on the roads you actually want to go on, then the GPS will route you along this route! And this is typically exactly what you want since you planned the route that way to begin with.
Now, if you do not plan the route (at all), then obviously the GPS has not received any instructions in that regard and will fall back to the default - and that is where the avoidances and route option would become relevant. But only then. This would be the way to go for someone who just wants some (sensible) routing without any planning via Rideplanner etc.

Planning a route with waypoints and then having avoidances active will make the two inputs interfere. You're sort of pulling the throttle while standing on the brake. Typically not useful if you want to drive forward. So decide which you want: brake or throttle. Avoidances or waypoints.

This has worked like a charm for me, anyway.

 

I just got back from a two day trip and I wish I would have seen this thread beforehand. Thanks for all the comments, I think I finally understand.