Have finished tiling shower stall & tub surround and am ready to grout. Do I grout first, leaving the vertical inside corners and bottom joint between the mosaic tile shower floor & vertical tile open for silicone caulking, or caulk those first, then grout the horizontal and middle joints after? Dumb thought here, but should I grout those plane changes, then caulk over them? Also, I have used silicone caulk before in place of grout, (for small projects) and have had a hard time achieving a good finish, as the silicone sticks to the tile, as opposed to the nice finish sponging the grout creates. Any recommendations for the silicone finishing?

I always grout first, leaving the corners ungrouted. Let the grout dry overnight or for a few hours, than caulk it. If you can get a color-matched grout caulk, it looks a lot better than clear silicone. Somebody else might have a better method/idea.

I like to caulk them without any grout behind too. I find that caulking over the grout will trap water that soaks into the grout...and then mold grows behind the caulk. If the joint is solid caulking, you don't get any moisture trapped behind. Colour match is great if you can match it. I've been having good luck with Translucent silicone. It takes on the surrounding colour and blends in really well. It's much better than clear, if you can find it.